Psych 311 Final
A graphical display for grouped frequency distributions with continuous data is called a A) histogram B) bar chart C) pie chart D) scatter gram
A
One difference between a repeated measures design and a matched samples design is that A) only one design involves observing the same participants in each group B) only one design eliminates between-persons variability C) only one design increases the power to observe an effect D) only one design is a type of related sample design
A
When reporting the results of a one-sample z test using APA format, the ________ do/does not need to be reported. A) critical values B) effect size C) Test statistic D) p value
A
A characteristic (usually numeric) that describes a sample is called a A) sample B) sample statistic C) population D) population parameter
B
A chi-square goodness-of-fit test shows that the frequencies observed fit well with those that were expected. Hence, the decision was to A) reject the null hypothesis B) retain the null hypothesis C) no decision was made
B
What is the z score for scores in the top 2.5%? A) .675 B) 1.96 C) .0124 D) .0250
B
What is the z score for scores in the bottom 5%? A) 1.645 B) -1.645 C) .4801 D) -0.050
B
2. In a factory that makes widgets, defective widgets are sometimes made. The probability of 0-2 defective widgets per 1000 widgets is .51. The probability of 3-5 defective widgets per 1000 is .24. What is the probability of more than 5 defective widgets? A) .75 B) .49 C) .25 D) 0
C
EXTRA CREDIT. The formula for the Spearman correlation coefficient was derived from the formula for___________________________________________________________ A) Two way between groups ANOVA B) Krabby patties (this is not the correct answer) C) Pearson r D) chi-square
C
The use of tables and graphs to summarize data is an example of A) inferential statistics B) interpretation C) descriptive statistics D) generalization
C
A researcher computes a 2 × 2 chi-square test for independence. What is the critical value for this test at a .05 level of significance? A) 3.84 B) 5.99 C) 7.81 D) 6.64
A
A researcher conducts a chi-square goodness-of-fit test in which k = 3 and x^2= 4.32. What is the decision for this test at a .05 level of significance? A) Retain the null hypothesis. B) Reject the null hypothesis. C) There is not enough information to answer this question.
A
A researcher conducts two t tests. Test 1 is a one-tailed test with a smaller sample size at a .05 level of significance. Test 2 is a one-tailed test with a larger sample size at a .05 level of significance. What do you know about the critical values for each test? A) Test 2 is associated with smaller critical values. B) Each test is associated with the same critical values. C) Test 1 is associated with smaller critical values. D) It depends; there is not enough information to answer this question.
A
A researcher measures the following correlation between cups of coffee consumed daily and daily work schedule. Which description best explains the relationship between these two factors? A) The more a person works, the more coffee he or she tends to drink. B) The less a person works, the more coffee he or she tends to drink. C) The more a person works, the less coffee he or she tends to drink. D)No linear pattern is evident.
A
A researcher measures the number of trials it takes two samples of participants to master a new task. In both samples, SS = 240. Sample A consisted of 12 participants and Sample B consisted of 18 participants. Which sample is associated with the largest variance? A) Sample A B) Sample B C) Both samples have the same variance. D) There is not enough information to answer this question.
A
A researcher records 17 scores. What is the median position of these scores? A) the 9th score in numeric order B) the average of the 9th and 10th scores in numeric order C) the average of the 8th and 9th scores in numeric order D) It's not possible to know this without the raw scores.
A
A researcher records the following data for the number of dreams recalled during a night of sleep for 10 college students: 3, 2, 4, 4, 3, 1, 1, 0, 2, and 0. Is the mean equal to the median in this example? A) Yes. B) No; the median is larger than the mean. C) No; the mean is larger than the median. D)There is not enough information to answer this question.
A
A researcher records the time (in seconds) that participants arrive late for a scheduled research study. Assuming these data are normally distributed, which measure of central tendency is most appropriate to describe these data? A) mean B) median C) mode D) range
A
A researcher runs an independent groups design and reports that the mean difference in response time to an auditory versus a visual cue is 0.83 seconds, with a pooled sample variance equal to 2.45. What is the effect size for this test using estimated Cohen's d? A) d = 0.53 B) d = 1.00 C) d = 0.34 D) d = 0.83
A
A researcher sampled 16 couples and measured the mean difference in their marital satisfaction. Each couple was paired and the differences in their ratings (on a 7-point scale) were taken. If the mean difference in satisfaction ratings for this sample was 1.8±2.0 ( ), then what is the decision at a .05 level of significance? A) Satisfaction ratings significantly differ, t(15) = 3.60. B) Satisfaction ratings significantly differ, t(14) = 3.60. C) Satisfaction ratings do not significantly differ, t(14) = 0.90. D) Satisfaction ratings do not significantly differ, t(15) = 0.90.
A
A researcher selects a sample of 16 participants from a population with a variance of 4. What is the standard error of the mean? A) less than 1 B) equal to 1 C) greater than 1 D) There is not enough information to answer this question.
A
A researcher selects a sample of 80 people and records the frequency of participants choosing a low, moderate, or high calorie dessert in a buffet. What are the degrees of freedom for this chi-square goodness-of-fit test? A) 2 B) 3 C) 79 D) 80
A
A researcher selects a sample of size 4 from a population of size 6. How many possible samples of this size can be selected using experimental sampling? A) 15 B) 30 C) 1,296 D) 4,096
A
A correlation coefficient can ______ demonstrate cause. A) always B) never C) mostly D) intermittently
B
A method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called A) guessing B) hypothesis testing C) random sampling D) level of significance
B
A professor grades 120 research papers and reports that the average score was an 80%. What do we know about the sum of the differences of these 120 scores from their mean of 80%? A) The sum of the differences is minimal. B) The sum of the differences is 80%, the same as the mean. C) The sum of the differences is equal to zero. D) It is impossible to know without knowing each of the 120 scores.
B
A researcher compares differences in positivity between participants in a low-, middle-, or upper-middle-class family. If she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects ANOVA? A) (3, 12) B) (2, 42) C) (2, 12) D) (3, 43)
B
A researcher computes a 2 × 3 chi-square test for independence. What is the critical value for this test at a .05 level of significance? A) 3.84 B) 5.99 C) 7.81 D) 12.59
B
A researcher computes a 4 × 6 chi-square test for independence with a sample of 120 participants, with x^2 = 14.79. What is the effect size for this result? A) 0.04 B) 0.20 C) 0.12 D) 0.35
B
Which of the following best describes a dependent variable? A) the sample variable B) the measured behavior C) the manipulated variable D) the population variable
B
Which of the following is an assumption for the two-independent sample t test, but not the one-sample t test? A) Random sampling B) Equal variances C) Normality D) Independence
B
Which proportion is largest in a z distribution? A) The proportion of area above the mean. B) The proportion of area between z = +1 and z = -1. C) The proportion of area greater than z = 1.0. D) The proportion of area less than z = 0.
B
Which rule states that when two outcomes are independent, the probability that these outcomes occur together is the product of their individual probabilities? A) additive rule B) multiplicative rule C) both A and B D) none of the above
B
While the expected value of the mean estimates the average outcome, the ________________ of a probability distribution estimates the distance that all other outcomes deviate from the mean. A. Median B. Standard deviation C. Mode D. Negative
B
A researcher has participants rate the likability of a sexually promiscuous person described in a vignette as being male (n = 20) or female (n = 12). The mean likability rating in each group was 4.0. If the null hypothesis is that there is no difference in likability ratings, then do likability ratings differ at a .05 level of significance? A) No, this result is not significant, t(30) = 1.00. B) Yes, this result is significant, p < .05. C) No, this result is not significant, t(30) = 0. D) There is not enough information to answer this question, because the variance in each sample is not given.
C
A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the total df? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122 A) 45 B) 8 C) 49 D) 43
C
A researcher measures the following correlation between number of years of education and life satisfaction: r = +0.08. What is the value of the coefficient of determination? A) 0.08 B) 0.16 C) 0.01 D) 0.11
C
A researcher measures the relationship between narcissism and willingness to help. If SSxy = 240, SSx = 320, and SSy = 410, then what is the value of the correlation coefficient? A) 0.002 B) 0.02 C) 0.66 D) 0.69
C
A researcher measures the relationship between two variables, X and Y. If SSxy = 340 and SSxSSy = 320,000, then what is the value of the correlation coefficient? A) 0.32 B) 0.34 C) 0.60 D) almost a zero correlation
C
A researcher obtains z = 1.45 for a one-sample z test. What is the decision for this test at a .05 level of significance? A) It depends on whether the test is one-tailed or two-tailed. B) to reject the null hypothesis C) to retain the null hypothesis D) There is not enough information to make a decision.
C
The estimated standard error in the t statistic uses the ________ to estimate the ________ when the population variance is unknown. A) population variance; sample variance B) degrees of freedom; sample size C) sample variance; population variance D) standard error; sample variance
C
The mean crying time of infants during naptime at a local preschool is 12 minutes (that's the population mean). The school implements a new naptime routine in a sample of 25 infants and records an average crying time of 8±4.6 (M±SD) minutes. Calculate t. A) 4.35 B) 0.92 C) -4.35 D) -0.92
C
The normal distribution has all of the following characteristics, except A) the mean can be any number B) it is mathematically defined C) the total area under the curve is greater than 1.0 D) the mean, median, and mode are equal
C
The one-sample z test is a hypothesis test used to test hypotheses A) concerning at least one population B) concerning the variance in a population C) concerning a single population with a known variance D) all of the above
C
The probability of committing a Type I error is stated by ________; the probability for committing a Type II error is stated by ________. A) the power; the power B) beta; alpha C) alpha; beta D) a p value; a p value
C
The probability of making zero to two errors per 1,000 keystrokes is 0.43, and the probability of making three to five errors per 1,000 keystrokes is 0.28. Find the probability (per 1,000 keystrokes) associated with making at least three errors. A) .29 B) .43 C) .57 D) .71
C
Using APA format, which value is typically given in parentheses when reporting the results for a t test? A) The estimate for standard error. B) The level of significance. C) The degrees of freedom. D) The value of the test statistic.
C
The median is an appropriate measure of central tendency for A) data that are positively skewed B) data that are negatively skewed C) data that are on an ordinal scale D) all of the above
D
(EXTRA CREDIT) A researcher assigned participants (n = 8 per group) to read vignettes describing a person engaging in either a helpful, hurtful, or neutral act. Different participants were assigned to each group and asked to rate how positively they viewed the person described in the vignette. What is the critical value for the one-way between-subjects ANOVA at a .05 level of significance? A) 3.47 B) 4.32 C) 3.44 D) 3.07
A
Which measure of effect size is most commonly reported with a t test? A) omega-squared B) Cohen's d C) eta-squared D) t statistic
B
A researcher selects two samples of 64 participants each. In the first sample the population mean was 10 and the variance was 16. In this second sample, the population mean was 25 and the variance was 9. Which sample will be associated with a larger standard error of the mean? A) Sample 1 B) Sample 2 C) None, both samples will have the same value for standard error D) There is not enough information to answer this question.
A
A type of related samples design in which participants are observed more than once is called a A) repeated measures design B) matched pairs design C) matched samples design D) both B and C
A
An animal researcher measures the number of times a rat presses a lever located at the right, center, and left of a cage for a food reward. What scale of measurement is the location of lever pressing? A) nominal B) ordinal C) interval D) ratio
A
An education counselor records the number of high school graduates enrolled in community colleges, four-year colleges, and universities. What scale of measurement is the type of college? A) nominal B) ordinal C) interval D) ratio
A
EXTRA CREDIT. A researcher decides to split scores on an exam into quartiles. She determines that a score of 64 is at the 25th percentile, a score of 74 is at the 50th percentile, and a score of 80 is at the 75th percentile. What is the interquartile range (IQR) for these data? A) 16 B) 10 C) 6 D) There is not enough information to answer this question.
A
Each of the following is an advantage for using the related samples design, except A) it increases the variability measured in a study B) it can be more practical C) it minimizes standard error D) it increases the power of a research design
A
Fill in the missing values for A and B in this frequency distribution table: Intervals Frequency 6.0-6.6 12 5.3-5.9 7 4.6-5.2 B 3.9-4.5 10 A-3.8 8 50 A) A = 3.2, B = 13 B) A = 3.1, B = 14 C) A = 3.3, B = 13 D) There is not enough information to complete this table.
A
How is the standard error of the mean typically reported in a graph? A) using error bars B) by plotting sample means C) by listing group names along the x-axis D) it is never reported in a graph
A
Procedures that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected best describes A) inferential statistics B) sample statistics C) descriptive statistics D) population parameters
A
Researchers measure data in a ________ to learn more about individuals in the larger _______ of interest. A) sample; population B) statistic; inference C) population; sample D) inference; statistic
A
State the critical value(s) for a t test using a two-tailed test at a .05 level of significance: t(20). A) ±2.086 B) ±0.687 C) ±2.093 D) ±1.725
A
The correlation coefficient measures the extent to which changes in one factor are _______ in a second factor. A) related to changes B) causing changes C) causing variability D) all of the above
A
The following distribution most closely approximates a A) normal distribution B) positively skewed distribution C) negatively skewed distribution D) multimodal distribution
A
The following is a summary of a one-way between-subjects ANOVA: F(2, 37) = 3.42, p < .05, = .12. How many participants were observed in this study? A) 40 B) 12 C) 39 D) 37
A
The mean of the sampling distribution of sample means is A) equal to the population mean B) equal to the population variance C) both A and B D) none of the above
A
The normal distribution is symmetrical, which means that A) scores above the mean are distributed the same as scores below the mean B) extreme scores are possible in a normal distribution C) there are an infinite number of possible normal distributions D) this characteristic has no practical implication
A
The point-biserial correlation coefficient is a measure of the direction and strength of the linear relationship between two variables, where A) one is continuous, and one is dichotomous B) both variables are on an ordinal scale C) one is at interval level or higher and one is ordinal D) both variables are on a nominal scale
A
The probability of making zero to two errors per 1,000 keystrokes is 0.43, and the probability of making three to five errors per 1,000 keystrokes is 0.28. Find the probability (per 1,000 keystrokes) associated with making more than five errors. A) .29 B) .43 C) .57 D) .71
A
The proportion or fraction of times an outcome is likely to occur is referred to as A) Probability B) a random event C) sample space D) Luck
A
The standard normal distribution is normally distributed with a mean of ____ and a variance of ____. A) 0; 1 B) 1; 0 C) any value; any positive value D) any positive value; any value
A
To compute a two-independent sample t test, a researcher has to know many values. Which of the following is NOT a value that the researcher must know to compute this test? A) the pooled population variance B) the sample mean for both samples C) the pooled sample variance D) the sample size for both samples
A
Two outcomes are said to be mutually exclusive when A) the probability of the two outcomes occurring together is equal to zero (p = 0) B) the probability of the occurrence of one outcome has no effect on the probability of the occurrence of the second outcome C) the probability of the two outcomes occurring together is greater than zero (p > 0) D) the probability of the two outcomes occurring together sums to one
A
What is a key distinction between parametric tests and nonparametric tests in terms of scales of measurement? A) Parametric tests are used for interval and ratio data, whereas nonparametric tests are used for nominal and ordinal data. B) Parametric tests are used for ordinal and nominal data, whereas nonparametric tests are used for interval and ratio data. C) Parametric tests are used for ordinal or interval data, whereas nonparametric tests are used for nominal data only. D) There is no distinction; both types of tests are used to analyze data on any scale of measurement.
A
Which design allows you to test an interaction effect? A) a two-way ANOVA B) an independent groups t-test C) a one-way ANOVA D) All of the above
A
Which is true of the chi-square distribution? A) It is positively skewed B) It is negatively skewed C) It is the same as a normal distribution D) None of the above
A
Which of the following is a key assumption for a chi-square goodness-of-fit test? A) The observed frequencies are independently recorded in each cell. B) The variance between groups is equal. C) There is no mean difference between groups. D) The proportion in each cell is equal to zero.
A
Which of the following is not one of the four steps to hypothesis testing? A) evaluate the plan B) compute the test statistic C) state the hypotheses D) set the criteria for a decision
A
Which of the following is the best explanation for why the standard deviation is almost always reported with the mean? A) The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation. B) The standard deviation is also a measure of central tendency, so it is important to report this value with the mean. C) The mean and standard deviation estimate basically the same thing, so these values are typically reported together. D) This is not true; the standard deviation is rarely reported with the mean.
A
Which of the following summarizes a t test that was significant and associated with a large effect size? A) t(12) = 2.95, p < .05, d = .82 B) t(22) = 3.02, p < .05, d = .36 C) t(30) = 1.03, p > .05, d = .20 D) t(60) = 1.76, p > .05, d = .45
A
A researcher determines that the probability of missing class among students at a local school is p = .16. Assuming that the school has 300 students enrolled, how many students can we expect to miss class on a given day? Hint: This is a binomial probability distribution. A) 252 students B) 48 students C) 16 students D) There is not enough information to answer this question.
B
A researcher measures the amount of coffee consumed by college students while studying during the final exam week. In her study, she found that students drink 2.3±0.8 (M±SD) cups of coffee per study session. Assuming the data are normally distributed, which of the following is the most appropriate conclusion? A) The average student drinks less than 2.3 cups of coffee per study session. B) Most students drink between 1.5 and 3.1 cups of coffee per study session. C) Most students drink between 2.3 and 3.9 cups of coffee per study session. D) Most students drink between 0.7 and 2.3 cups of coffee per study session.
B
A researcher measures the correlation of the time it takes participants to complete two tasks purported to measure the same cognitive skill. Participant times are converted to ranks from fastest to slowest. If SigmaD^2 = 165 and n = 20, then what is the decision for this correlation test? A) Retain the null hypothesis because the critical value exceeds the calculated value. B) Reject the null hypothesis because the calculated value exceeds the critical value. C) Retain the null hypothesis because the calculated value exceeds the critical value. D) Reject the null hypothesis because the critical value exceeds the calculated value.
B
A researcher measures the following correlation between cost of produce and number of units sold. Which description best explains the relationship between these two factors? A) As the cost of produce increases, so also do the number of units sold. B) Less expensive produce is associated with an increased number of units sold. C) Less expensive produce is associated with a decreased number of units sold. D) No linear pattern is evident.
B
A researcher observes a correlation of values from 2 to 10 points and draws conclusions about the full range of values in the population from 0 to 21 points. Which limitation for correctly interpreting a correlation coefficient did the researcher violate? A) reverse causality B) restriction of range C) a confound variable D) homoscedasticity
B
A researcher records the frequency of participants selecting one of four new slogans for an advertising campaign. If it was expected that among 200 people polled there would be no preference for any one slogan, then what was the expected frequency for each slogan. A) 25 people B) 50 people C) 100 people D) 200 people
B
A researcher records the time in seconds it takes a sample of participants to walk alone through a dark portion of campus. The researcher computes SS = 1,000. Assuming that a sample of 11 participants was observed in this study, what is the standard deviation for these data? A) 1 seconds B) 10 seconds C) 100 seconds D) 1000 seconds
B
A researcher records the time it takes (in seconds) for participants to respond (by pressing a key) to a familiar versus an unfamiliar word flashed onto a computer screen. In this study, the difference in response time for each participant is compared. The type of design described here is called a A) mixed measures design B) repeated measures design C) independent samples design D) matched samples design
B
A researcher records the time it takes to complete a memory task in a sample of 25 participants. He finds that the average participant completed the test in 43 seconds. The average time to complete this task is called a(n) A) population parameter B) sample statistic C) inferential statistic D) time trial
B
A researcher reports that the probability of a college student living on campus is p = .38. If a small local college has 2,000 students enrolled, then what is the standard deviation of college students living on campus? Hint: This is a binomial probability distribution. A) 471.2 students B) 21.7 students C) 760 students D) There is not enough information to answer this question.
B
A researcher selects a sample of 24 participants and has them complete a survey on dating preferences. In this example, what are the degrees of freedom for sample variance and what does this figure represent? A) df = 24; it represents the number of scores that are free to vary in a sample. B) df = 23; it represents the number of scores that are free to vary in a sample. C) df = 23; dividing SS by df makes the sample variance a biased estimator of the population variance. D) df = 24; dividing SS by df makes the sample variance an unbiased estimator of the population variance.
B
A researcher selects a sample of 32 participants who are assigned to participate in a study with one group. What are the degrees of freedom for this test? A) 30 B) 31 C) 32 D) There is not enough information to answer this question.
B
A researcher wants to know the probability of being named on the honor roll from a population where 8% of students are on the honor roll. If the researcher selects a sample of 400 students, then what is the mean number of students expected to be on the honor roll? Hint: This is a binomial distribution, where p = 0.08 and q = 0.92. A) 29 B) 32 C) 368 D) 200
B
A therapist goes through her records and finds that 200 of her 400 patients showed significant improvement in mental health over the past year. Hence, the probability of her patients showing significant improvement in mental health is A) .05 B) .50 C) 200 D) 400
B
As a general rule, the larger the degrees of freedom for a chi-square test, A) the smaller the critical value will be B) the larger the critical value will be C) the smaller the level of significance will be D) the larger the level of significance will be
B
Computing a one-way between-subjects ANOVA is appropriate when A) the levels of one or more factors are manipulated B) different participants are observed one time in each of two or more groups for one factor C) the same participants are observed in each of two or more groups for one factor D) all of the above
B
Correlations can be depicted in a graph called a _______________ A) bar chart B) scatter plot C) pie chart D) continuation plot
B
When SS = 100 and N = 25, the population standard deviation is equal to __ A) 10 B) 2 C) 4 D) There is not enough information to determine the population standard deviation.
B
EXTRA CREDIT!! What is the central limit theorem? A) It explains that sample means will vary minimally from the population mean. B) It explains that a sampling distribution of possible sample means is approximately normally distributed, regardless of the shape of the distribution in the population. C) It explains that if we select a sample at random, then on average we can expect the sample mean to equal the population mean. D) all of the above
B
Each of the following statements are true, except that A) increasing the sample size will decrease standard error B) the larger the sample size, the larger the standard error C) the larger the standard deviation in the population, the larger the standard error D) both B and C
B
Homogeneity of variance is an assumption for the one-way between-subjects ANOVA. What does this assumption mean? A) that one observation has no effect on the likelihood of another observation B) that the variance is equal in each population from which samples are selected C) that the population being sampled from is normally distributed D) that participants are randomly selected to participate in a sample
B
If the expected frequencies equal to observed frequencies for a chi-square test for independence, what do we conclude? A) the degrees of freedom for the test are equal to 0 B) the test statistic value is equal to 0 C) the frequencies observed fit well with the frequencies expected D) both B and C
B
In the stem-and-leaf display, each number to the right of the vertical line is referred to as a ________; the numbers to the left of the vertical line are called the ________. A) stem; leaf B) leaf; stem C) digit; place D) place; digit
B
Is a one-sample z test reported differently for one-tailed and two-tailed tests? A) It can be reported differently when the effect size is large. B) No, the same values are reported. C) It depends on whether the results were significant. D) Yes, only significant results for a two-tailed test are reported.
B
Measures of variability can range in value from A) - ∞ to + ∞ B) 0 to + ∞ C) It depends on whether the variability is positive or negative. D) It depends on the value of the mean for a given distribution.
B
Post hoc tests are computed A) to determine if groups means differ, even for tests in which the decision is to retain the null hypothesis. B) Following a significant ANOVA test to make pairwise comparisons. C) Prior to conducting a hypothesis test. D) To determine which set of degrees of freedom can be attributed to the variability between-groups.
B
Regardless of the number of scores in a distribution, the range only includes ___ score(s) in its calculation. A) one B) two C) at most two D) the average
B
Regardless of the shape of the distribution in the population, the sampling distribution of sample variances approximates a A) normal distribution B) positively skewed distribution C) negatively skewed distribution D) multimodal distribution
B
Scores far from the mean are located in the ________ of a normal distribution. A) Body B) Tails C) most sensitive areas D) most uncertain areas
B
The Spearman rank-order correlation coefficient is a measure of the direction and strength of the linear relationship between two ________ variables. A) nominal B) ordinal C) interval D) ratio
B
The ________ is the middle value in a distribution of scores that are listed in numeric order. A) mean B) median C) mode D) range
B
The appropriate correlation coefficient for measuring the direction and strength of the linear relationship between one continuous and one dichotomous variable is A) the Spearman rank-order correlation coefficient B) the point-biserial correlation coefficient C) the phi correlation coefficient D) none of the above
B
The correlation coefficient ranges from -1.0 to +1.0, with values closer to ±1.0 indicating A) a more positive relationship between two factors B) a stronger relationship between two factors C) that two factors are less likely to be related D) that the correlation is due to outliers
B
The degrees of freedom for the sample variance A) are equal to the sample size B) are equal to the sample size minus one C) can vary between - and + D) both B and C
B
The probability of a college student being employed is p = .35. The probability of a student being employed and dropping out of college is p = .20. Hence, the probability of a student dropping out of college, given that he or she is employed, is A) p = .07 B) p = .57 C) p = .55 D) There is not enough information to answer this question.
B
The probability of making zero to two errors per 1,000 keystrokes is 0.43, and the probability of making three to five errors per 1,000 keystrokes is 0.28. Find the probability (per 1,000 keystrokes) associated with making at most two errors. A) .29 B) .43 C) .57 D) .71
B
The range of scores in each interval of a grouped frequency distribution is called the A) simple frequency B) interval width C) real range D) grouped data
B
To construct a pie chart, first distribute the data as A) cumulative percentages B) relative percentages C) cumulative frequencies D) cumulative relative percentages
B
What is the description of SS (Sum of squares) in words? That is, what does it stand for? A) Sum or deviations of scores from the mean. B) Sum of squared deviations of scores from the mean. C) Sum of the square roots of scores. D) Sum of the squared scores divided by the mean.
B
What is the implication for the tails of a normal distribution being asymptotic? A) that scores above the mean are distributed the same as scores below the mean B) that extreme scores are possible in a normal distribution C) that there are an infinite number of possible normal distributions D) that this characteristic has no practical implication
B
What terms refer to each of the following measures, respectively: mean, median, and mode. A) middle, most, and average B) average, middle, and most C) average, most, and middle D) most, average, and middle
B
What values are distributed along the x-axis for a sampling distribution of the sample mean? A) scores B) sample means C) sample variances D) both B and C
B
A normal distribution has a mean equal to 53. What is the standard deviation of this normal distribution if 2.5% of the proportion under the curve lies to the right of x = 66.72? (Round your answer to two decimal places) A) -7.00 B) 0.14 C) 7.00 D) 49.00
C
A researcher asks participants to estimate the height (in inches) of a statue that was in a waiting area. The researcher records the following estimates: 40, 46, 30, 50, and 34. If the researcher removes the estimate of 40 (say, due to an experimenter error), then the value of the mean will____ (Hint: Calculate the mean first!) a) decrease b) increase c) remain the same d) become negative
C
A researcher computes a 3 × 5 chi-square test for independence. What are the degrees of freedom for this test? A) 3 B) 5 C) 8 D) 15
C
A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the MSBG ? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122 A) 2 B) 0.125 C) 8 D) 0.50
C
The assumptions for performing Pearson r test are A) linearity B) homoscedasticity C) normality (for example, for variable x and for variable y) D) all of the above
D
A cumulative percentage summary that indicates the percentage of scores at or below a given value is called a A) relative percentage B) relative frequency C) percentile rank D) cumulative frequency
C
A researcher records the sound (in decibels) during a series of lessons taught by a substitute teacher at a local elementary school. In his study, he found that the sound was 80±6 (M±SD) decibels. Assuming the data are normally distributed, which of the following is an appropriate conclusion? A) 68% of classes were between 68 and 80 decibels. B) 5% of classes were louder than 68 decibels. C) 95% of classes were between 68 and 92 decibels. D) all of the above
C
A researcher reports a significant mean difference in a given population. If she computes both eta-squared and omega-squared to measure the effect size, then which estimate will be the most conservative? A) It depends on the value of the t statistic. B) eta-squared C) omega-squared D) It depends on the sample size.
C
A researcher reports that the size of an effect in some population is d = 0.88. Which of the following is an appropriate interpretation for d? A) Mean scores were significant by 0.88 points in the population. B) The effect observed in the population was significant. C) Mean scores shifted 0.88 standard deviations in the population. D) Mean scores were significant by 0.88 points in the sample.
C
A researcher selects a sample of 36 dog owners and measures their responsiveness to two types of pictures: one depicting the humane treatment of dogs and one depicting the inhumane treatment of dogs. The researcher finds that responsiveness significantly differed, t = 3.243. Use eta-squared to compute the proportion of variance for this result. A)n^2 = 0.25 B)n^2 = 0.21 C)n^2 = 0.23 D) There is not enough information to answer this question.
C
A researcher wants to determine how many participants will take less than 24 seconds to complete a cognitive performance task. If he constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer his question? A) a simple frequency distribution B) a relative frequency distribution C) a cumulative frequency distribution from the bottom up D) a cumulative frequency distribution from the top down
C
An example of a binomial variable includes A) time (in seconds) B) weight (in pounds) C) sex (male, female) D) all of the above
C
An unanticipated variable not accounted for in a research study that could be causing or associated with observed changes in one or more measured variables is called A) reverse causality B) restriction of range C) a confound variable D) homoscedasticity
C
Based on the effect size conventions, d = 0.60 is a A) large effect size B) small effect size C) medium effect size
C
Bayes' theorem is often applied to a variety of ________ probability situations, including those related to statistical inference. A) generic B) absolute C) conditional D) Fixed
C
EXTRA CREDIT. The following is a simple frequency distribution table. If we convert this frequency distribution to relative percentages, which of the following gives the corresponding percentages in each interval listed from the top down. Intervals Frequency 44-46 6 41-43 4 38-40 5 35-37 10 32-34 5 30 A) 20%, 33%, 50%, 67%, 100% B) 0.2, 0.13, 0.17, 0.33, 0.17 C) 20%, 13%, 17%, 33%, 17% D) 6, 10, 15, 25, 30
C
For an analysis of variance, the term "one-way" refers to A) the number of statistical tests in the design B) the direction that traffic should follow on a road C) the number of factors in the design D) the number of ways that the data can be analyzed
C
For the experimental sampling strategy, A) the order in which a participant is selected matters B) sampling is with replacement C) sampling is without replacement D) participants are not sampled from the population, but instead are sampled from other samples already drawn
C
How many possible samples of size 2 can be selected from a population of 5 using theoretical sampling? A) 5 B) 10 C) 25 D) 32
C
Hypothesis testing is also called A) random testing B) effect size C) significance testing D) Type III error
C
If the standard deviation of a probability distribution is 9, then the variance is A) 3 B) 9 C) 81 D) Unknown
C
In a game, the probability of winning money is p = .16, the probability of losing money is p = .54, and the probability of breaking even is p = .30. What is the probability of winning or losing money in this game? A) .16 B) .54 C) .70 D) 1.00
C
State the problem with this simple frequency distribution. Intervals Frequency 8-10 4 6-8 7 4-6 3 2-4 6 0-2 9 A) The interval width is too small. B) The interval width is unequal. C) The class intervals overlap. D) The number of intervals is too small.
C
State whether the first area is bigger, the second area is bigger, or the two areas are equal: the area to the left of z = 0.80, or the area to the right of z = -0.80. A) The first area is bigger. B) The second area is bigger. C) The two areas are the same.
C
Suppose that a researcher selects a sample of participants from a population. If the shape of the distribution in this population is positively skewed, then what is the shape of the sampling distribution of sample means? A) approximately positively skewed B) approximately negatively skewed C) approximately normally distributed D) There is not enough information to answer this question, because the population mean and variance are not given.
C
The ________ is an inferential statistic used to determine the number of standard deviations in a t distribution that a sample mean deviates from the mean value or mean difference stated in the null hypothesis. A) degrees of freedom B) t distribution C) t statistic D) standard error
C
The appropriate correlation coefficient for measuring for the direction and strength of the linear relationship between two dichotomous variables is A) the Spearman rank-order correlation coefficient B) the point-biserial correlation coefficient C) the phi correlation coefficient D) none of the above
C
The assumption that there is an equal variance or scatter of data points dispersed along the regression line is referred to as A) normality B) linearity C) homoscedasticity D) restriction of range
C
The correlation coefficient is used to measure the ________ and ________ of the linear relationship between two factors. A) date; time B) mean; variance C) significance; effect size D) strength; direction
D
What does it mean to say that the sample mean is an unbiased estimator of the population mean? A) The sample means will vary minimally from the population mean. B) The sampling distribution of possible sample means is approximately normally distributed, regardless of the shape of the distribution in the population. C) If we select a sample at random, then on average we can expect the sample mean to equal the population mean. D) all of the above
C
What values are distributed along the x-axis for a sampling distribution of the sample variance? A) scores B) sample means C) sample variances D) both B and C
C
When computing a chi-square goodness-of-fit test, the frequency expected in a given cell should never be less than A) the sample size B) the number of cells C) Five D) 100
C
When would a researcher calculate a population mean? A) when data are measured for of a portion of individuals from a population B) when the sample mean is not available C) when data are measured for all members of a population D) when it is not possible to measure all data in a population
C
Which of the following indicates the strongest correlation? A) r = -0.57 B) r = +0.78 C) r = -0.90 D) r = +0.88
C
Which of the following is a statistical procedure used to test hypotheses about the discrepancy between the observed and expected frequencies in two or more nominal categories? A) one-way ANOVA B) analysis of regression C) chi-square test D) all of the above
C
Which of the following measures of effect size can be reported with a 3 × 4 chi-square test for independence? A) proportion of variance B) the phi coefficient C) Cramer's V D) all of the above
C
Which of the following statements regarding the null hypothesis is true? A) A decision in hypothesis testing is made about the alternative hypothesis, not the null hypothesis. B) The null hypothesis is the only hypothesis stated in hypothesis testing. C) The null hypothesis always makes statements about a population parameter. D) all of the above
C
Which of the following would not be reported for a correlation? A) the sample size B) the coefficient of determination C) the critical values for each test D) the strength and direction of the correlation
C
You are interested in measuring the construct, reinforcement. Which of the following measures for this construct is quantitative and continuous? A) the number of rewards received B) the type of reward (food, money) C) the size of a reward in grams D) the rating of a reward on a scale from 1 (not reinforcing) to 7 (very reinforcing)
C
________ allows researchers to describe (1) how far mean scores have shifted in the population, or (2) the percentage of variance that can be explained by a given variable. A) Power B) Significance C) Effect size D) Probability
C
Many nonparametric tests are called ________ because they make no assumptions regarding the shape of the distribution in the population. A) parametric tests B) skewed-distribution tests C) significance-free tests D) distribution-free tests
D
The Friedman test is used as a nonparametric alternative to which parametric test? A) related samples t-test B) two-independent sample t-test C) one-way between-subjects ANOVA D) one-way within-subjects ANOVA
D
Increasing the number of observations or samples in a study will decrease the standard error (standard error of the mean). This is known as A) Bob (not the right answer) B) the law of diminishing returns C) the theoretical law of estimates D) the law of large numbers
D
(EXTRA CREDIT) Using a two-way between-subjects ANOVA with Factor A (Gender: male, female) and Factor B (Type of employment: blue collar, white collar), a researcher found that salary for men and women significantly varied across the levels of the second factor (type of employment). That is, the effect of gender depended on type of employment. In this study, the researcher found a significant A) post hoc test B) main effect of Factor A C) main effect of Factor B D) interaction
D
A chi-square goodness-of-fit test leads to a decision to retain the null hypothesis. Which of the following correctly explains this decision? A) frequencies observed were significantly different from frequencies expected at each level of the categorical variable B) frequencies observed were significantly different from frequencies expected across the levels of the categorical variable C) frequencies observed were significantly different from frequencies expected within and between expected frequencies D) Frequencies observed were statistically similar to the frequencies expected at each level of the categorical variable
D
A researcher compares the amount of college debt (in dollars) that undergraduate students incur up to their four-year degree. College debt is on what scale of measurement? A) nominal B) ordinal C) interval D) ratio
D
A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the MSE ? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122 A) 8 B) 0.125 C) 0.50 D) 2
D
A researcher conducts two chi-square tests. The 2 × 2 chi-square was 2 = 3.82. The 2 × 3 chi-square was 2 = 5.02. Which chi-square test resulted in a decision to reject the null hypothesis at a .05 level of significance? A) the 2 × 2 chi-square B) the 2 × 3 chi-square C) both chi-square tests results in a decision to reject the null hypothesis D) none; both chi-square tests result in a decision to retain the null hypothesis
D
A researcher records the following data for the number of bids made on a sample of items sold at an auction. Based on the table, what was the probability that an item had 7 bids made on it? Number of Bids Frequencies 3 5 4 12 5 7 6 6 7 10 A) 5 B) 10 C) .10 D) .25
D
A researcher reports the following results for a chi-square test: x^2 (1) = 5.386, p < .05 (V = 0.224). If this test were a test for independence, then how many groups (cells) were observed? A) 1 B) 2 C) 3 D) 4
D
A researcher selects a sample of 100 participants from a population with a mean of 38 and a standard deviation of 20. About 68% of the sample means in this sampling distribution should be between a sample mean of A) 34 and 40 B) 34 and 38 C) 38 and 44 D) 36 and 40
D
A researcher selects a sample of 6 males and 11 females. She asks participants to rate the likelihood they would do female-stereotyped jobs (such as nursing or school teaching) on a scale from 1 = not likely at all to 5 = very likely. Men indicated that they would be less likely to do these jobs (M = 2.1) compared with women (M = 4.3). What is the weighted mean for this entire sample of 17 participants? A) 2.1 B) 4.3 C) 3.2 D) 3.5
D
A scientist finds two results. Result #1 is that higher education is associated with a larger annual income. Result #2 is that fewer calories consumed is associated with less visits to the doctor. How would you characterize these two results? A) Result #1 shows a positive correlation and result #2 shows a negative correlation. B) Result #1 shows a negative correlation and result #2 shows a positive correlation. C) Both results show a negative correlation. D) Both results show a positive correlation.
D
A therapist observes that spouses are more likely to forgive their partners for lying to them if they find out the truth from their spouse and not a third party. In this example, the dependent variable is A) the number of partners B) the spouse C) lying D) forgiveness
D
Compared to the two-independent sample t test, the related samples design decreases A) effect size B) significance C) power D) standard error
D
Computing a one-sample t test is appropriate when A) the population variance is unknown B) participants are observed one time C) participants are assigned to only one group D) all of the above
D
Descriptive statistics are procedures used to A) summarize a set of scores or observations B) organize a set of scores or observations C) make sense of a set of scores or observations D) all of the above
D
EXTRA CREDIT!! A researcher randomly selects a sample of athletes and reports that their average score on a health and fitness scale is 23. Based on the characteristics of the sample mean, what does this say about the mean in the population? A) Nothing; it was just a sample. B) There is no way to know without knowing the size of the sample. C) It tells us that the mean in the population is no less than 23. D) We expect that the population mean is equal to 23 because the sample mean is an unbiased estimator of the population mean.
D
EXTRA CREDIT. A psychologist tests whether cravings for heroin and relapse are independent. The following table lists the observed frequencies, with the expected frequencies listed in parentheses. Calculate chi-square for these data. Chi-square = Relapse Yes No Cravings Yes 22 (17.07) 11 (15.93) 33 No 8 (12.93) 17 (12.07) 25 30 28 N=58 A) -6.84 B) 0 C) 2.62 D) 6.84
D
Each of the following is an example of a binomial distribution, except A) the number of heads in ten flips of a fair coin B) the number of males and females in a sample C) the number of votes for or against a candidate D) the time it takes to complete a driving test
D
For the related samples t test, assuming that all other values remain constant, then as samples size increases, A) the power to detect an effect increases B) the estimate for standard error decreases C) the value of the test statistic increases D) all of the above
D
Imagine you are a journal editor. A researcher reports means and standard deviations for groups for a study that required running a chi-square test. Is there a problem? If so, what is it? A) There's no problem. B) It is meaningful to calculate means for chi-square data, but not standard deviations. C) It's not meaningful to calculate means and SDs for chi-square data because the data represent rank-orderings on the dependent variable. D) It's not meaningful to calculate means and SDs for chi-square data because the data represent frequency counts.
D
The normality assumption states that the population of X and Y scores form a bivariate ("two variable") normal distribution, such that A) the population of X and Y scores are normally distributed B) for each X score, the distribution of Y scores is normally distributed C) for each Y score, the distribution of X scores is normally distributed D) all of the above
D
The numerator of the correlation coefficient measures the extent to which two variables A) vary together B) vary independently C) covary D) both A and C
D
The probability of making zero to two errors per 1,000 keystrokes is 0.43, and the probability of making three to five errors per 1,000 keystrokes is 0.28. Find the probability (per 1,000 keystrokes) associated with making at most five errors. A) .29 B) .43 C) .57 D) .71
D
The sample variance is an unbiased estimator of the population variance A) when dividing SS by n B) when dividing SS by df C) when dividing SS by n - 1 D) both B and C
D
The sign test is used as a nonparametric alternative to which parametric test? A) one-sample t-test B) two-independent sample t-test C) related samples t-test D) both A and C
D
The size of a population is symbolized as ________, whereas the size of a sample is symbolized as ________. A) mu; M B) M;mu C) n; N D) N; n
D
The t distribution is similar to the z distribution except A) it is associated with scores being more likely in the tails of the distribution B) it is associated with greater variability C) it is characterized by "thicker" tails compared with the z distribution D) all of the above
D
The test statistic for a related samples t test makes tests concerning a single sample of A) participant scores B) raw scores C) original data D) difference scores
D
The unit of measurement distributed along the x-axis of a standard normal distribution is referred to as a A) standardized score B) x-score C) normalized deviation D) z score
D
Three research methods common to research in the behavioral sciences are A) experimental, transferable, and correlation B) experimental, variable, and correlational C) experimental, operational, and quasi-correlational D) experimental, quasi-experimental, and correlational
D
We convert r to a chi-square statistic for which of the following correlation tests? A) Pearson B) Spearman C) point-biserial D) phi
D
What is the definition of "power" in statistics usage? A) The likelihood of retaining a true null hypothesis B) The likelihood of rejecting a true null hypothesis C) The likelihood of retaining a false null hypothesis D) The likelihood of rejecting a false null hypothesis
D
What is the percentile point at the 80th percentile in the following distribution? Frequency Percentile Rank 9-11 100% 6-8 80% 3-5 40% 0-2 20% A) 2 B) 6 C) 7 D) 8
D
What is the typical level of significance for a hypothesis test in behavioral research? A) .001 B) .50 C) .10 D) .05
D
When the probability of one outcome changes depending on the occurrence of a second outcome, these outcomes are referred to as A) mutually exclusive B) Complementary C) Independent D) Conditional
D
Which of the following is NOT a characteristic of probability? A) Probability varies between 0 and 1. B) Probability can never be negative. C) Probability can be stated as a fraction or decimal. D) Probability is most useful for describing fixed events.
D
Which of the following is NOT a characteristic of the mean? A) Add a score above the mean and the mean will increase. B) Add a score below the mean and the mean will decrease. C) Delete a score below the mean and the mean will increase. D) Delete a score above the mean and the mean will increase.
D
Which of the following is an assumption for computing any type of independent sample t test? A) Data were obtained from a sample that was selected using a random sampling procedure. B) The probabilities of each measured outcome in a study are independent. C) Data in the population being sampled are normally distributed. D) all of the above
D
Which of the following is an example of a distribution with NO variability? A) scores: 3, 5, 4, 4, 5, and 3 B) scores: 3, 3, 3, 3, 33, and 3 C) scores: 1, 2, 3, 4, 5, and 6 D) scores: 5, 5, 5, 5, 5, and 5
D
Which of the following is an example of a parametric test? A) analysis of variance B) one-sample t-test C) Pearson correlation D) all of the above
D
Which of the following is consistent with the empirical rule? A) 68% of all scores lie within one standard deviation of the mean. B) 95% of all scores lie within two standard deviations of the mean. C) 99.7% of all scores lie within three standard deviations of the mean. D) all of the above
D
Which of the following is recorded using a chi-square goodness-of-fit test and a chi-square test for independence? A) variance B) frequency observed C) frequency expected D) both B and C
D
Which of the following is true about the computational formula for variance? A) The computational formula will always produce the same solution as the definitional formula (give or take rounding errors). B) It is a short-cut method for calculating variance when the population or sample size is large. C) It is derived mathematically from the definitional formula. D) all of the above
D
