Psych 311 Final exam
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 (.43 + .28)
.71(.43+.28)
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.
0 to +infinity
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
0.66
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
0:1
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 (4-1 * 6-1) B) 30 C) 1,296 D) 4,096
15 ( 4-1 * 6-1)
A researcher reports the following results for a chi-square test: χ 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
2
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
2
A researcher finds that 12% of participants make between 3-5 visits to a physician each year. What are the real limits for this interval? A) 3-5 B) 2.5-5.5 C) 2.5-3.5 D) equal to the sum of the products for the previous interval
2.5-5.5
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
20%, 13%, 17%, 33%, 17%
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
3.84
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 (400 * .08) C) 368 D) 200
32 (400*.08)
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 (300 * .16 !n*p) C) 16 students D) There is not enough information to answer this question.
48 students
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
50 people
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 (find the z score for 7, or for 66.72) D) 49.00
7.00 ( find the z score for 7, or for 66.72)
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
8
If the standard deviation of a probability distribution is 9, then the variance is A) 3 B) 9 C) 81 D) unknown
81
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
95% of classes were between 68 and 92 decibels
You read about a study testing whether night shift workers sleep the recommended 8 hours per day. Assuming that the population variance of sleep (per day) is unknown, what type of t test is appropriate for this study? A) one-sample t test B) two-independent sample t test C) There is not enough information to answer this question.
one sample t test
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
one-way within subjects ANOVA
One difference between a repeated measures design and a matched samples design is that A) only one design is a type of related sample design B) only one design increases the power to observe an effect C) only one design involves observing the same participants in each group D) only one design eliminates between-persons variability
only one design involves observing the same participant in each group
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
ordinal
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) B) C) D) p = .07 p = .57 (.2/.35) p = .55 There is not enough information to answer this question.
p=.57 (.2/.35) p=.55
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
percentile rank
The denominator of the test statistic for a related samples t test A) compares mean differences observed to the mean differences stated in a null hypothesis B) is the sum of the difference scores for each participant C) provides an estimate of the error associated with the original scores D) provides an estimate of the error associated with the difference scores
provides an estimate of the error associated with the difference scores
A researcher conducts a study in which the population variance of difference scores between two groups is unknown. What type of t test is most appropriate for this study? A) one-sample t test B) two-independent sample t test C) related samples t test D) There is not enough information to answer this question.
related samples t test
A researcher conducts a study in which the same participants are observed across each level of the independent variable. If there are only two levels of the independent variable, then what type of t test is appropriate for this study? A) one-sample t test B) two-independent sample t test C) related samples t test D) There is not enough information to answer this question.
related samples t test
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
repeated measures design
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
sampling without replacement
Correlations can be depicted in a graph called a _______________ A) bar chart B) scatter plot C) pie chart D) continuation plot
scatter plot
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
scores above the mean are distributed the same as scores below the mean
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
strength, direction
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) t distribution B) t statistic C) standard error D) degrees of freedom
t statistic
Which of the following summarizes a t test that was significant and associated with a large effect size? A) t(22) = 3.02, p < .05, d = .36 B) t(30) = 1.03, p > .05, d = .20 C) t(60) = 1.76, p > .05, d = .45 D) t(12) = 2.95, p < .05, d = .82
t(12)=2.95, p<.05, d=.82
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
tails
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 1 is associated with smaller critical values. B) Test 2 is associated with smaller critical values. C) Each test is associated with the same critical values. D) It depends; there is not enough information to answer this question.
test 2 is associated with smaller critical values
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
that extreme scores are possible in a normal distribution
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.
the average of the 8th and 9th scores in numeric order
All other things being equal, as the sample size increases, what happens to the critical value for a related samples t test (or for any t test, for that matter)? A) The critical value increases. B) The critical value decreases. C) The critical value does not change. D) It depends on the value of the test statistic.
the critical value decreases
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
the larger the sample size, the larger the standard error
Which of the following best describes an independent variable? A) the sample variable B) the measured behavior C) the manipulated variable D) the population variable
the manipulated variable
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
the measured behavior
The mean crying time of infants during naptime at a local preschool is 12 minutes. 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. Test whether this new naptime routine reduced crying time at a .05 level of significance. A) The new naptime routine significantly reduced crying time, t(24) = -4.35, p < .05. B) The new naptime routine did not reduce crying time, t(24) = -4.35, p < .05. C) The new naptime routine did not reduce crying time, t(24) = 0.92, p > .05. D) The new naptime routine significantly reduce crying time, t(24) = 0.92, p < . 05.
the new nap time routine significantly reduced crying time , t(24)=-4.35, p<.05
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
the point-biserial correlation coefficient
To compute a related samples 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 estimated standard error for difference scores B) the population variance of difference scores C) the sample size or number of pairs of scores D) the sample variance of difference scores
the population variance of difference scores
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 then z = 1.0. D) The proportion of area less than z = 0.
the proportion of area between z=+1 and z=-1
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)
the size of a reward in grams
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
the smaller the critical value will be
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.
the sum of differences is equal to zero
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
the total area under the curve is greater than 1.0
Which of the following is not 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.
the variance between groups is equal
The size of a population mean is symbolized as ________, whereas the size of a sample mean is symbolized as ________. A) μ;M B) M;μ C) n;N D) N;n
u:M
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
using error bars
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 it 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
when data are measured for all members of a population
Each deviation in the numerator for variance is squared because A) without squaring each deviation, the solution for SS would be zero B) this inflates the value for variance, making it more accurate C) without squaring each deviation, the solution could be negative D) both A and C
without squaring each deviation, the solution for SS would be zero
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
z score
Two researchers (A and B) compute a two-independent sample t test. For both tests, the mean difference between the two groups is 10, but the standard error is smaller for Researcher A. Which test is more likely to result in a decision to reject the null hypothesis? A) Researcher A. B) Researcher B. C) The likelihood is the same for both researchers. D) There is not enough information to answer this question.
Researcher 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.
Sample A
A researcher measures deviant behavior in a sample of 12 children from abusive homes (Sample A). Another researcher measures the same behavior in a sample of 18 children from abusive homes (Sample B). Which sample is associated with larger degrees of freedom? A) Sample A B) Sample B C) Each sample has the same degrees of freedom. D) There is not enough information to answer this question.
Sample B
Computing a one-sample t test is appropriate when A) participants are assigned to only one group B) the population variance is unknown C) participants are observed one time D) all of the above
all of the above
Computing a two-independent sample t test is appropriate when A) different participants are assigned to each group B) the population variance is unknown C) participants are observed one time D) all of the above
all of the above
For the related samples t test, assuming that all other values remain constant, then as samples size increases, A) the value of the test statistic increases B) the power to detect an effect increases C) the estimate for standard error decreases D) all of the above
all of the above
The t distribution is similar to the z distribution except A) it is associated with greater variability B) it is characterized by "thicker" tails compared with the z distribution C) it is associated with scores being more likely in the tails of the distribution D) all of the above
all of the above
Which of the following is an assumption for computing any type of independent sample t test? A) Data in the population being sampled are normally distributed. B) Data were obtained from a sample that was selected using a random sampling procedure. C) The probabilities of each measured outcome in a study are independent. D) all of the above
all of the above
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
all of the above
The test statistic for a related samples t test makes tests concerning a single sample of A) raw scores B) difference scores C) participant scores D) original data
difference scores
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
distribution-free tests
Give the names for two commonly used measures of effect size for t tests that give you the proportion of variance explained in the DV.
eta squared
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) the frequency observed D) five
five
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
forgiveness
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
frequencies observed were statistically similar to the frequencies expected at each level of the categorical variable
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
homoscedasticity
Which of the following is the assumption that there is an equal variance of data points dispersed along the regression line? A) normality B) linearity C) homoscedasticity D) restriction of range
homoscedasticity
Each of the following is an advantage for using the related samples design, except A) it can be more practical B) it minimizes standard error C) it increases the power of a research design D) it increases the variability measured in a study
it increases the variability measured in a study
What is the z score for scores in the bottom 5%? A) 1.645 B) -1.645 C) .4801 D) -0.050
-1.645
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
5.99
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=3.2, B=13
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
Cramer's V
Which measure of effect size is most commonly reported with a t test? A) eta-squared B) omega-squared C) t statistic D) Cohen's d
cohens D
As_____ _________________ increases, the power to detect an effect increases.
sample size
A researcher records differences in ratings of emotion among participants watching either a drama or a romance film. Assuming that the population variance is unknown, what type of t test is appropriate for this study? A) one-sample t test B) two-independent sample t test C) There is not enough information to answer this question.
two independent sample t test
What are the degrees of freedom for the related samples t test? A) (nD - 1) B) (n - 1) (n - 1) C) (n - 1) + (n - 1) D) (n - 1) - (n - 1)
(nD-1)
State the critical value(s) for a t test using a two-tailed test at a .05 level of significance: t(20). A) ±1.725 B) ±2.093 C) ±2.086 D) ±0.687
+- 2.086
A researcher matched 30 participants on intelligence (hence 15 pairs of participants), and then compared differences in emotional responsiveness to two experimental stimuli between each pair. For this test, what are the critical values, assuming a two-tailed test at a .05 level of significance? A) ±2.042 B) ±2.045 C) ±2.131 D) ±2.145
+-2.145
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) 32 B) 30 C) 31 D) There is not enough information to answer this question.
31
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
all of the above
The sample variance is: A) an unbiased estimator of the population variance B) associated with n - 1 degrees of freedom C) computed by dividing SS by df D) all of the above
all of the above
Each of the following is an example of quantitative data, except A) weight in ounces B) income in dollars C) political affiliation D) age in years
political affiliation
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
positively skewed distribution
A researcher compares the difference in the amount of texting by students in class during the first week and last week of classes. The type of design described here is called a A) repeated measures design B) matched samples design C) both A and B
repeated measures design
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
sample means
The estimated standard error in the t statistic uses the ________ to estimate the ________ when the population variance is unknown. A) sample variance; population variance B) population variance; sample variance C) standard error; sample variance D) degrees of freedom; sample size
sample variance; population variance
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
sample variances
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
sample; population
Eta-squared is computed ______ for the one-sample, and the two-independent sample t tests. A) Differently B) Infinitely C) Similarly D) Semantically
similarly
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.
sum of squared deviations of scores from the mean
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.
approximately normally distributed
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
are equal to the sample size minus one
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
both b and c
A researcher conducts a study, but has low power to detect an effect. Which of the following is one way in which the research can increase power? A) Make the alpha level smaller. B) Increase the sample size. C) Study a population with a larger standard deviation. D) Conduct the study again with the same sample size.
increase the sample size
A correlation coefficient can ______ demonstrate cause. A) always B) never C) mostly D) intermittently
never
Is a one-sample t test reported differently for one-tailed and two-tailed tests? A) No, the same values are reported. B) It depends on whether the results were significant. C) Yes, only significant results for a two-tailed test are reported. D) It can be reported differently when the effect size is large.
no, the same values are reported
The following distribution most closely approximates a A) normal distribution B) positively skewed distribution C) negatively skewed distribution D) multimodal distribution
normal distribution
The use of tables and graphs to summarize data is an example of A) inferential statistics B) interpretation C) descriptive statistics D) generalization
descriptive statistics
Rejecting a true null hypothesis is a Type_________________error.
I
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
both a and c
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
both b and 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
chi square test
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
conditional
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
conditional
When reporting the results of a one-sample z test using APA format, the ________ does not need to be reported. A) Test statistic B) p value C) effect size D) critical values
critical values
A researcher reports that mean ratings of liking for some food are 0.8±2.4 (M ±SD). If the null hypothesis was that the mean equals 0, then what is the effect size for this test using estimated Cohen's d? A) d = 0.33; small effect size B) d = 0.33; medium effect size C) d = 3.00; large effect size D) There is not enough information to answer this question.
d=0.33; medium effect size
A researcher 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; medium effect size B) d = 0.53; large effect size C) d = 0.34; small effect size D) d = 0.34; medium effect size
d=0.53; medium effect size
A researcher reports that the mean difference in the body weight of rats following a pharmacological versus control treatment is 14 grams, with a pooled sample variance equal to 256. What is the effect size for this test using estimated Cohen's d? A) d = 0.06; small effect size B) d = 0.08; small effect size C) d = 0.88; large effect size D) There is not enough information to answer this question.
d=0.88; large effect size
A researcher records the following data: 4, 4, 4, 4, and 3. How would you describe the variability of these data? A) It is equal to zero because scores are approximately the same. B) It is negative because 3 is less than the other scores in the distribution. C) It is very small (close to 0) because scores are approximately the same. D) It is very large (much greater than 0) because 3 is an outlier in the data.
it is very small (close to 0) because scores are approximately the same
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
leaf;stem
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.
less expensive produce is associated with an increased number of units sold
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 (square root of the variance aka standard dev divided by the sqrt of N) B) equal to 1 C) greater than 1 D) There is not enough information to answer this question.
less than 1 (square root of the variance aka standard deviation divided by the square root of N)
A researcher asks a sample of brothers and sisters to rate how positive their family environment was during childhood. In this study, the differences in ratings between each brother and sister pair were compared. The type of design described here is called a A) repeated measures design B) matched samples design C) both A and B
matched samples design
Which of the following is a type of related samples design in which different participants are actually observed in each group, but treated statistically as if they are the same persons in each group. A) repeated measures design B) matched samples design C) pre-post design D) within-subjects design
matched samples design
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.
most students drink between 1.5 and 3.1 cups of coffee per study session
A researcher reports a significant effect with t(14) = 3.24. Compute eta-squared for this result. A) η2 = 0.43 (large effect size) B) η2 = 0.43 (medium effect size) C) ω2 = 0.37 (large effect size) D) ω2 = 0.37 (medium effect size)
n^2=0.43 ( large effect size)
Is a one-sample z test reported differently for one-tailed and two-tailed tests? A) No, the same values are reported. B) It depends on whether the results were significant. C) Yes, only significant results for a two-tailed test are reported. D) It can be reported differently when the effect size is large.
no, the same values are reported
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 ratings in each group were 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) Yes, this result is significant, p < .05. B) No, this result is not significant, t(30) = 0. C) No, this result is not significant, t(30) = 1.00. D) There is not enough information to answer this question, because the variance in each sample is not given.
no, this result is not significant, t(30)=0
A researcher conducts two chi-square tests. The 2 × 2 chi-square was χ2 = 3.82. The 2 × 3 chi-square was χ2 = 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
none; both chi square tests result in a decision to retain the null hypothesis
Two researchers (A and B) compute a one-sample t test. For both tests, the mean difference between the sample and value stated in the null hypothesis is 5, but the standard error is smaller for Researcher A. Which test is more likely to result in a decision to reject the null hypothesis? A) Researcher A. B) Researcher B. C) The likelihood is the same for both researchers. D) There is not enough information to answer this question.
researcher A
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
retain the null hypothesis
A researcher conducts a chi-square goodness-of-fit test in which k = 3 and χ 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.
retain the null hypothesis