Behavioral Statistics Final Exam

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

η2 is computed ______ for the one-sample and the two-independent-sample t tests. a) differently b) infinitely c) similarly d) semantically

c

A local elementary school determined that the average number of volunteers for their "Step into Spring" annual fundraiser has been 14 persons on average (per event). After taking additional measures to recruit volunteers this year, they got 28 people to volunteer. Test whether these additional measures increased the number of volunteers at a .05 level of significance. a) Yes, because the number of volunteers doubled; this is a significant increase. b) No, this is not a significant increase because the error term is too large. c) This would have been significant if it were a two-tailed test. d) There is not enough information to answer this question.

d

A researcher conducts a 2 × 3 between-subjects ANOVA. She finds a significant interaction, where SSAXB = 120 and SST = 518. What is the effect size for this test using η2? a) 0.43 b) 4.32 c) there is not enough information to answer this question d) 0.23

d

The size of a population is symbolized as ______, whereas the size of a sample is symbolized as ______. a) μ; M b) M; μ c) n; N d) N; n

d

Without changing the value of error variance, the ______ the between-groups variability, the more likely we are to retain the null hypothesis. a) smaller b) larger

smaller

A researcher computes a 2 × 3 factorial ANOVA. In this example, how many interactions can be observed? a) 1 b) 2 c) 3 d) 6

a

The sampling distribution of the mean and the sampling distribution of the variance (when dividing SS by n - 1) a) are both unbiased estimators. b) both follow the central limit theorem. c) are both associated with minimal variance. d) all of these.

a

A researcher computes a 2 × 4 between-subjects ANOVA. What are the degrees of freedom for Factor B for this study? a) 4 b) 2 c) 3 d) 8

c

When df are in the denominator, 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 these.

d

______ 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) Significance b) Probability c) Power d) Effect size

d

A researcher tests whether the dosage level of some drugs (low, high) causes significant differences in health. To do this, the researcher randomly assigns rat subjects to receive a low or high dosage of the drug and records health-related measures in both groups. The type of method described is a) experimental. b) quasi-experimental. c) correlation. d) operational.

a

A professor compares final exam scores in his psychology class to final exam grades in another comparable professor's class. Assuming that the population variance of exam scores is unknown, what type of t test is appropriate for analyzing differences between these classes? a) one-sample t test b) two-independent-sample t test c) There is not enough information to answer this question.

b

A researcher increases the sample size, which will: a) increase the value of standard error. b) decrease the value of standard error. c) reduce variability in the population. d) increase variability in the population.

b

A researcher conducts a study in which k = 6 and n = 6 per group. What are the critical values for the one-way between-subjects ANOVA at a .05 level of significance? a) 3.70 b) 3.47 c) 2.53 d) 2.42

c

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

c

Which source of variation, if significant, is typically analyzed first? a) main effect b) the interaction

b

A psychologist reviews her notes for all her patients and determines that on average her patients complete therapy in 24 days. The average time to complete therapy among all her patients is called a(n) a) population parameter. b) sample statistic. c) inferential statistic. d) time trial.

a

A researcher computes a 2 × 3 between-subjects ANOVA test in which 11 participants were observed in each condition. If F = 5.20 for both main effect tests and the A × B interaction test, then the decision for each test a) will be significant for both main effects and the A × B interaction b) will be significant for Factor B and the A × B interaction c) there is not enough information to answer this question d) will be significant for Factor A, but not Factor B

a

A researcher measures the time (in seconds) it takes children to complete a basic reading skills task. What type of graphical display would be most appropriate for summarizing the frequency of children falling into different intervals of time? a) histogram b) bar chart c) scatter gram d) all of these

a

A researcher randomly assigned 32 children to observe a short clip depicting either their favorite superhero, a parent, a teacher, or no person at all (n = 8 per group). If SSBG = 30 and SSE = 104, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? a) retain the null hypothesis. b) reject the null hypothesis. c) there is not enough information to answer this question

a

Each of the following are interval scale measurements, except a) duration of sleep (in hours). b) scores on an SAT (scholastic assessment test). c) the latitude and longitude of birth for those suffering from schizophrenia. d) the body temperature (in degrees Fahrenheit) increase during exercise.

a

The ______ is the percentage of scores with values that fall below a specified score in a distribution. a) percentile rank b) interval c) relative frequency d) percentile point

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

Which of the following is an assumption for computing a one-way between-subjects ANOVA? a) all of these. b) Participants were selected to participate using a random procedure. c) One observation has no effect on the likelihood of another observation. d) The population being sampled from is normally distributed.

a

A researcher computes a 4 × 4 between-subjects ANOVA and finds two significant main effects and a significant interaction. What is typically the next appropriate step? a) compute simple main effect tests for each main effect b) compute simple main effect tests for the interaction c) compute pairwise comparisons for the interaction d) compute pairwise comparisons for each main effect

b

A researcher conducts two studies using the one-way between-subjects ANOVA. The sum of squares between groups is larger in Study 1 than in Study 2; the sum of squares total is smaller in Study 1 than in Study 2. Using η2, in which study will the effect size be larger? a) Study 2 b) Study 1 c) there is not enough information to answer this question

b

A researcher conducts two t tests. Test 1 is a two-tailed test with a smaller sample size at a .05 level of significance. Test 2 is a two-tailed test with a larger sample size at a .05 level of significance. What do you know about the degrees of freedom for each test? a) Test 1 is associated with larger degrees of freedom. b) Test 2 is associated with larger degrees of freedom. c) Each test is associated with the same degrees of freedom. d) It depends; there is not enough information to answer this question.

b

A researcher finds that the mean difference in productivity between employees working the morning shift (n = 16) and the night shift (n = 10) is 5.0 units, and the estimates standard error for the difference is 2.7 units. If the null hypothesis states that there is no difference in productivity, then is this result significant at a .05 level of significance for a two-tailed test? a) Yes, this result is significant. b) No, this result is not significant. c) There is not enough information to answer this question.

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 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.

b

A researcher measures the number of tasks completed by participants during a 5-min multitasking session. If the number of tasks completed is distributed normally as 6.3 ± 1.0 (M ± SD) tasks, then what is the probability that participants completed less than eight tasks? a) .0446 b) .9554 c) .4554 d) The probability is not listed in the unit normal table.

b

A researcher records the following times (in seconds) that it took a group of mice to complete a maze: 23 ± 4.1 (M ± SD). The top 10% of mice finishing with the fastest times will be placed in a "maze bright" group. What is the cutoff time to be placed in this group? a) 17.75 s b) 28.25 s c) faster than 16 s d) There is not enough information to answer this question.

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

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 sample variance b) the pooled population variance c) the sample size for both samples d) the sample mean for both samples

b

Two researchers (A and B) compute a one-sample t test. For both tests, the standard error is the same, but the mean difference between the sample and value stated in the null hypothesis 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.

b

What are the two decisions that researchers can make in hypothesis testing? a) accept or reject the null hypothesis b) retain or reject the null hypothesis c) accept or reject the null hypothesis and retain or reject the null hypothesis

b

Which of the following is an example of a distribution with NO variability? a) scores: 3, 5, 4, 4, 5, and 3 b) scores: 5, 5, 5, 5, 5, and 5 c) scores: 1, 2, 3, 4, 5, and 6 d) None of these; all distributions have at least some variability greater than 0.

b

A researcher assigns 21 adolescents to rate the likability of a person described in a vignette as having one of three personality traits. An equal number of participants are assigned to each group. If Fobt = 4.08 for this study, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? a) retain the null hypothesis b) there is not enough information to answer this question c) reject the null hypothesis

c

A researcher computes two 2 × 2 between-subjects ANOVAs. In Study 1, he observes eight participants in each cell; in Study 2, he observes 12 participants in each cell. Which study is associated with a larger value for degrees of freedom for the A × B interaction? a) Study 2 b) Study 1 c) both studies have the same degrees of freedom for the A × B interaction

c

A researcher conditions rats to fear a tone that was sounded just prior to a brief shock. To measure fear following this conditioning, she records the number of lever presses by each rat in the presence and in the absence of the tone. It was hypothesized that reduced lever pressing in the presence of the tone was evidence for a conditioned fear response in rats. If the researcher tested this hypothesis at a .05 level of significance (two-tailed test), then what is her decision if she computes t = -2.842 in a sample of eight rats. a) Retain the null hypothesis; there is evidence for a conditioned fear response. b) Retain the null hypothesis; there is no evidence for a conditioned fear response. c) Reject the null hypothesis; there is evidence for a conditioned fear response. d) Reject the null hypothesis; there is no evidence for a conditioned fear response.

c

A researcher placed male rodents in the presence and absence of a conspecific male. Cortisol (a stress hormone) levels were compared at both times. 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

c

A researcher records the following data for the number of complaints filed (per day) following a controversial policy change at a local business: 3, 8, 5, 0, 4, 6, 2, 1, 1, 4, 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.

c

A researcher records the number of job openings among small businesses. She finds that the probability that a small business has 0 job openings is p = .22; 1 job opening is p = .45; 2 job openings is p = .08; and 3 job openings is p = .25. What is the probability that a small business has at least 2 job openings? a) .08 b) .25 c) .33 d) .67

c

A researcher selects a sample of 49 participants from a population with a mean of 12 and a standard deviation of 3.5. What is the probability of selecting a sample mean that is at least equal to the population mean? a) .50 b) equal to the probability of selecting a sample mean that is at most equal to the population mean c) .50 and equal to the probability of selecting a sample mean that is at most equal to the population mean d) none of these

c

It is most appropriate to report effect size with a significant result. Why is it generally inappropriate to report effect size with nonsignificant results? a) Because insignificant results will always have an effect size equal to 0. b) Because insignificant results indicate that an effect size is also not significant. c) Because it makes little sense to report the size of an effect that you just concluded doesn't exist. d) Because the probability of the size of an effect varies depending on the significance of the effect size measure.

c

Most behavior is believed to ______ a normal distribution. a) be exactly equal to b) not resemble at all c) approximate

c

The ______ is the sum of all scores (in a sample or population) divided by the number of scores summed. a) mode b) median c) mean d) range

c

The normal distribution has all of the following characteristics, except that a) it is symmetrical. b) its distribution is theoretical. c) the total area under the curve is greater than 1.0. d) the mean, median, and mode are equal.

c

The sample variance is computed by dividing SS by ______, whereas the population variance is computed by dividing SS by ______. a) N; df b) df; n - 1 c) df; N d) n - 1; df

c

Two researchers analyze the same data set. Researcher A uses a two-independent-sample t test and decides to retain the null hypothesis. Researcher B uses a related-samples t test and decides to reject the null hypothesis. Which of the following is a likely explanation for the disparity in the decisions made? a) The two-independent-sample t test had greater power to detect the effect. b) The two-independent-sample t test was associated with fewer degrees of freedom. c) The related-samples t test had greater power to detect the effect. d) The related-samples t test was associated with more degrees of freedom.

c

Which of the following requires the calculation of a real range? a) frequency distributions for categorical b) frequency distributions for ungrouped data c) frequency distributions for grouped data d) frequency distributions that do not use real data

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

A professor finds that the average SAT score among all students attending his college is 1150 ± 150 (μ ± σ). He polls his class of 25 students and finds that the average SAT score is 1200. Suppose he computes a one-sample z test at a .05 level of significance. What is his decision? a) to reject the null hypothesis b) to retain the null hypothesis c) to reject the null hypothesis for a two-tailed test, but to retain the null hypothesis for an upper-tailed test d) to reject the null hypothesis for an upper-tailed test, but to retain the null hypothesis for a two-tailed test

d

A researcher computes a 2 × 3 between-subjects ANOVA in which six participants are observed in each cell. What are the degrees of freedom error for this study? a) 36 b) 71 c) 60 d) 30

d

A researcher computes a one-sample z test in two studies. Both studies used the same alpha level, placed the rejection region in both tails, and measured the same sample mean. The researcher selects a sample of 30 participants in Study 1 and decides to retain the null hypothesis. She selects a sample of 60 participants in Study 2 and decides to reject the null hypothesis. Which of the following is the best explanation for why the decision was different in Study 1 and Study 2? a) The different decisions in Study 1 and Study 2 are not possible because all values were the same. b) The different decisions in Study 1 and Study 2 are not possible because the researcher tested the same hypothesis. c) The different decisions in Study 1 and Study 2 are due to an error the researcher made in the first hypothesis test. d) The different decisions in Study 1 and Study 2 are possible because the second test was associated with greater power to detect an effect.

d

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

d

A researcher records the amount of time spent studying by male and female college students in a dormitory versus a library setting. Different participants were observed in each group. What type of statistical design is appropriate for this study? a) one-way within-subjects ANOVA b) one-way between-subjects ANOVA c) one-way within-subjects ANOVA and two-way between-subjects ANOVA d) two-way between-subjects ANOVA

d

A researcher reports "the average patron (n = 22) in a local bar consumed more than twice the number of drinks (per day) on weekends (M = 5.4 drinks) compared to weekdays (M = 2.3 drinks)." Although not stated directly, how do we know that the patrons in this study constitute a sample and not a population of patrons at this local bar? a) We can't know for sure because this was not stated directly. b) The notation for a sample mean was used. c) The notation for a sample size was used. d) Both the notation for a sample mean was used and the notation for a sample size was used.

d

By definition, the probability of an outcome or event is a) the proportion of times an outcome is likely to occur. b) the fraction of times an outcome is likely to occur. c) particularly useful for predicting the likelihood of random events. d) all of these.

d

Computing a two-independent-sample t test is appropriate when a) different participants are assigned to each of two groups. b) the population variance is unknown. c) participants are observed one time in a given group. d) all of these.

d

Following a significant one-way between-subjects ANOVA in which k > 2, what is the next appropriate step? a) summarize the data and interpret the data; no further tests are required b) interpret the data; no further tests are required c) summarize the data; no further tests are required d) conduct post hoc tests

d

Given the same set of data for a population and sample, would the mean for both data sets be equal? a) No, the population mean would be larger. b) No, the sample mean would be larger. c) Yes, but only if the sample size equaled the population size. d) Yes, this would be true anytime both data sets are the same.

d

Grouped data can be distributed a) as a range of values. b) with upper and lower boundaries. c) into intervals. d) all of these.

d

If the value of the test statistic is in the rejection region, then a) p < .05. b) the decision is to reject the null hypothesis. c) the value of the test statistic is larger than the critical value. d) all of these.

d

The degrees of freedom for error is called ______. a) degrees of freedom error b) degrees of freedom denominator c) degrees of freedom within groups d) all of these

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) when dividing SS by df and when dividing SS by n - 1.

d

The term "between-subjects" refers to ______. a) the type of post hoc test conducted b) the type of effect size estimate measured c) observing the same participants in each group d) observing different participants one time in each group

d

Which of the following is NOT an assumption for computing a two-way between-subjects ANOVA? a) The population being sampled from is normally distributed. b) Participants were selected using a random procedure. c) One observation has no effect on the likelihood of another observation. d) There is homogeneity of variance and homogeneity of covariance.

d

Which of the following is a possible value for the standard deviation of a normal distribution? a) -∞ b) 0 c) -2 d) 0.5

d

Which of the following is a scenario in which increasing sample size will increase power? a) when the effect size is small b) when the effect size is large c) when the probability of a Type I error is small d) all of these

d

Which of the following statements is the appropriate way to read the degrees of freedom for an ANOVA with 10 participants in each of four groups? a) 4 and 36 degrees of freedom b) 3 or 36 degrees of freedom c) 4 and 10 degrees of freedom d) 3 and 36 degrees of freedom

d

A researcher selects a sample of 121 participants from a population with a mean of 32 and a standard deviation of 22. What is the standard error of the mean? a) 32 b) 2.0 c) 0.5 d) There is not enough information to answer this question

b

A researcher measures the weight (in ounces) of newborn infants in the month of March. What type of graphical display would be most appropriate for summarizing the frequency of infants falling into different intervals of weight? a) histogram b) bar chart c) scatter gram d) all of these

a

A researcher reports a significant effect with t(14) = 3.24. Compute η2 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)

a

A researcher reports that the effectiveness of a new marketing campaign significantly increased sales compared with the previous campaign strategy, t(49) = 2.562, p < .05. Use η2 to interpret the effect size for this result. a) 12% of the variability in marketing effectiveness can be accounted for by the new marketing strategy. b) 12% of the standard error can be accounted for by the effectiveness of the marketing strategy. c) Marketing effectiveness shifted 0.12 standard deviations above the mean in the population. d) 12% of the variability in marketing effectiveness can be accounted for by the new marketing strategy and 12% of the standard error can be accounted for by the effectiveness of the marketing strategy.

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) all of these.

a

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) without squaring each deviation, the solution for SS would be zero, and without squaring each deviation, the solution could be negative.

a

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

a

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.

c