Stats Midterm 1
If we built on Doob and Gross's study of horn-honking behavior to compare the time it takes for people to honk at an older car versus the time to honk at an expensive newer car, we could set it up as: a. an independent sample design. b. a repeated measures design. c. neither an independent sample design nor a repeated measures design. d. It could be designed either way, depending upon our needs.
It could be designed either way, depending upon our needs.
Which of the following was NOT an advantage of repeated measures designs discussed in the text? a. It allows us to avoid problems associated with variability from subject to subject. b. It helps to control for extraneous variables. c. It is easier to calculate the statistics. d. It requires fewer subjects that other designs.
It is easier to calculate the statistics.
If the critical value of t associated with the above formula is 2.12, what would you conclude about your means? a. There is a significant difference between the means. b. There is a significant difference between the standard deviations. c. There is no significant difference between the means. d. p > .05
There is a significant difference between the means.
If we have two related samples, the power of our test will: a. increase as the correlation between the two samples increases. b. increase as the correlation between the two samples decreases. c. be at its maximum when the correlation is zero. d. The correlation is irrelevant.
increase as the correlation between the two samples increases.
A harmonic mean can be used to calculate the mean sample size for unequal sample sizes. For a(n) ________ the values of k would equal ________. a. related means t test; 3 b. related means t test; 2 c. independent samples t test; 3 d. independent samples t test; 2
independent samples t test; 2
The likelihood that a statistical test will permit researchers to correctly reject a false null hypothesis is called the ______________of a test. A) significance B) power C) criterion D) alpha level
Power
In an analysis of variance for repeated measures the estimate of error variation is called: A) between group variation. B) summary variation. C) residual variation. D) estimated variation.
residual variation
In the multiple-baseline design across individuals, the treatment is administered: A) to all individuals in the study at the same time. B) many times to each individual. C) during the common baseline period for all individuals. D) successively to one individual at a time.
successively to one individual at a time
If we use the standard approach to solve for the necessary sample size so that we have power = .75 in a two-sample t test, the value of N that we will obtain from the tables is: a. the number of subjects we will need in each group. b. the number of subjects we will need overall. c. the number of groups we will need to run. d. the number of subjects that we actually have available.
the number of subjects we will need in each group.
In the formula for t, 1.73 is: a. the standard deviation of the sample. b. the standard deviation of the population. c. the standard error of the mean. d. the difference between the means.
the standard error of the mean
A repeated measures t test is more likely to lead to rejection of the null hypothesis if: a. subjects show considerable variability in their change scores. b. many subjects show no change. c. some subjects change a lot more than others. d. the degree of change is consistent across subjects.
the degree of change is consistent across subjects.
The text suggested that the highest value of power that we are likely to be able to afford, assuming that we don't have huge differences between our groups, is something like: a. .20 b. .50 c. .80 d. .95
.80
The standard error of the mean would normally be written: a. 4302 b. 0.043 c. 430 d. 43
0.043
In the formula for t, there are ________ pairs of observations in the study. a. 17 b. 34 c. 18 d. 4.18
17
If the standard deviation of the population is 15 and we repeatedly draw samples of 25 observations each, the resulting sample means will have a standard error of: a. 2 b. 3 c. 15 d. 0.60
3
Mean scores in Tetris were recorded for both math majors and English majors. The mean score for math majors was 20,752 (s12 = 851, N1 = 17) and the mean score for English majors was 14,922 (s22 = 395, N2 = 56). The pooled variance would probably be closest to which value? a. 800 b. 623 c. 500 d. 900
500
All of the following increase the magnitude of the t statistic and/or the likelihood of rejecting H_0 EXCEPT: a. a greater difference between the sample mean and the population mean. b. an increase in sample size. c. a decrease in sample variance. d. a smaller significance level ().
A smaller significance level (∝)
With a one-sample t test, the value of t is: a. always positive. b. positive if the sample mean is too small. c. negative whenever the sample standard deviation is negative. d. positive if the sample mean is larger than the hypothesized population mean.
Positive if the sample mean is larger than the hypothesized population mean
When we speak about pooling variances we are referring to: a. averaging the two groups' variances. b. using the variance of the larger group. c. adding up the variances in each of two groups and dividing by 2. d. taking the variance of both sets of data combined.
averaging the two groups' variances.
In deciding whether or not to pool the variances in calculating a t score, one should consider: a. the differences in the sample variances. b. the differences in the sample sizes. c. both the differences in the sample variances and the differences in the sample sizes. d. neither the differences in the sample variances nor the differences in the sample sizes.
both the differences in the sample variances and the differences in the sample sizes.
The probability of a Type I error can be reduced by: A) decreasing the probability of a Type II error. B) changing alpha from .05 to .01. C) changing alpha from .05 to .10. D) accepting the null hypothesis.
changing alpha from .05 to .01
The effect size is generally denoted by: a. beta (). b. alpha (). c. d-hat (). d. delta ().
d-hat
Results that are "statistically significant": A) prove that the research hypothesis is true. B) indicate the null hypothesis is true. C) indicate that the research hypothesis is false. D) do not prove that the research hypothesis is true.
do not prove that the research hypothesis is true.
A Type I error arises when we: A) reject a true null hypothesis. B) reject a false null hypothesis. C) fail to reject a false null hypothesis. D) fail to reject a true null hypothesis.
reject a true null hypothesis.
The most important characteristic of two independent samples is a. we measure the same subjects at two separate times. b. the subjects in one sample are part of the same family as subjects in the other sample. c. the set of scores for one sample is uncorrelated with the scores in the other sample. d. the subjects in a group are people who know each other.
the set of scores for one sample is uncorrelated with the scores in the other sample
Which of the following is not a source of bias in case studies? A) socially desirable responses in a client's report of his or her behaviors B) the study of individuals with rare disorders C) distortions in the client's memory for past events D) inaccuracies in the therapist's observations of the client's behavior
the study of individuals with rare disorders
As the value of the mean difference score decreases: a. the t score increases. b. the t score decreases. c. the t score stays the same. d. You cannot predict how the t score will be affected.
the t score decreases.
Which of the following raises ethical concerns peculiar to the ABAB design? A) the use of aversive stimuli in treatment B) the excessive length of time it takes to complete a study C) the withdrawal of a beneficial treatment D) the deception required to establish a control group
the withdrawal of a beneficial treatment
If we have calculated a confidence interval and we find that it does NOT include the population mean: a. we must have done something wrong in collecting data. b. our interval was too wide. c. we made a mistake in calculation. d. this will happen a fixed percentage of the time.
this will happen a fixed percentage of the time
Which of the following would most likely NOT be independent samples? a. Group 1 contains wives and Group 2 contains their husbands. b. Group 1 contains women and Group 2 contains men. c. Group 1 contains dyslexic children and Group 2 contains non-dyslexic children. d. Group 1 contains smokers and Group 2 contains nonsmokers.
Group 1 contains wives and Group 2 contains their husbands.
When we are using a two-tailed hypothesis test, the null hypothesis is of the form: a. H1 : 50. b. H1 : < 50. c. H1 : > 50. d. H0 : = 50.
H_0 ∶ μ=50
We want to study the mean difference in autonomy between first-born and second-born children. Instead of taking a random sample of children we take a random sample of families and sort the children into first- and second-born. The dependent variable is a measure of autonomy. This experiment would most likely employ: a. a repeated measures analysis. b. an independent measures analysis. c. a correlation coefficient. d. a scatterplot.
Repeated measures analysis
Suppose that we know that the sample mean is 18 and the population standard deviation is 3. We want to test the null hypothesis that the population mean is 20. In this situation we would: a. reject the null hypothesis at = .05. b. reject the null hypothesis at = .01 c. retain the null hypothesis. d. We cannot solve this problem without knowing the sample size.
We cannot solve this problem without knowing the sample size
Which of the following patterns provides considerable evidence in an ABAB design that the treatment caused the behavior change? A) when the behavior remains the same across both of the baseline and treatment stages B) when the behavior remains constant when the treatment is introduced but changes when the treatment is withdrawn C) when the behavior changes both when the treatment is introduced and when the treatment is withdrawn D) when the behavior changes when the treatment is introduced and when the behavior stays constant when the treatment is withdrawn
when the behavior changes both when the treatment is introduced and when the treatment is withdrawn
If we reject the null hypothesis with a two-tailed test, we would side with which of the following alternatives? a. µFT = µC b. µFT µC c. µFT < µC d. µFT > µC
µFT µC
A baseline in a single-subject experimental design will be most effective in detecting a change due to the treatment if the baseline has a(n): A) decreasing trend. B) increasing trend. C) highly variable pattern. D) stable pattern.
stable pattern.
If we knew the population mean and variance, we would expect: a. the sample mean would closely approximate the population mean. b. the sample mean would differ from the population mean by no less than 1.96 standard deviations only 5% of the time. c. the sample mean would differ from the population mean by no more than 1.64 standard deviations only 5% of the time. d. the sample mean would differ from the population mean by more than 1.96 standard errors only 5% of the time.
The sample mean would differ from the population mean by more than 1.96 standard errors only 5% of the time.
What is the power in an experiment with two independent groups when the null hypothesis is true? a. .05 b. .95 c. .05/2 d. undefined
Undefined
When we are worrying about power we are most concerned with: a. a Type I error. b. a Type II error. c. the right answer to the wrong question. d. none of these.
a Type II error
The level of significance in psychological research is equivalent to: A) a Type II error. B) .50. C) a Type I error. D) the probability of rejecting a false null hypothesis.
a Type II error.
In calculating power we calculate a statistic called delta. This statistic is: a. the effect size. b. the sample size. c. a combination of the effect size and the sample size. d. the difference we are looking for.
a combination of the effect size and the sample size.
A statistically significant outcome is one that has ________likelihood of occurring if the null hypothesis is true. A) no B) a significant C) a large D) a small
a small
The baseline stage of a single-subject experimental design is useful to researchers because behavior during the baseline stage allows the researcher to: A) get an initial idea of whether the treatment will be effective. B) describe behavior before administering the treatment and predict what behavior will be like in the future without treatment. C) determine the best way to administer the treatment in light of the individual's behavior during the baseline. D) All of these
describe behavior before administering the treatment and predict what behavior will be like in the future without treatment.
Null hypothesis significance testing begins with the assumption that the performance of two or more groups: A) does not differ. B) differs only slightly. C) differs at a value of p < .05. D) differs significantly.
does not differ.
An effect size measure for an independent groups design with more than two means is: A) eta squared. B) Cohen's d. C) Cohen's r. D) F squared.
eta squared.
If we have two experiments in which the groups are equally different, the one with the larger power will be the one that: a. had the larger sample size. b. had the smaller level of . c. had the larger . d. assigned subjects randomly.
had the larger sample size.
Which of the following is one of the advantages of the case study method? A) it is a rich source of ideas for developing hypotheses B) it is nomothetic research C) it provides definitive support for a theory D) it permits intensive study of common, everyday phenomena
it is a rich source of ideas for developing hypotheses
When people such as Cohen say that a medium size difference has an effect size of .50, they are saying that we want the power for: a. one mean being half as large as another. b. one mean being half a point larger than another. c. one mean being half a standard deviation larger than another. d. one mean being based on half as many subjects as the other.
one mean being half a standard deviation larger than another.
If the omnibus analysis of variance for a complex design does not reveal a statistically significant interaction effect, the next step is to determine if the: A) simple main effects are statistically significant. B) overall main effects are statistically significant. C) simple interaction effect is statistically significant. D) comparisons of two means are statistically significant.
overall main effects are statistically significant.
To increase power, the easiest variable to control in designing an experiment is usually: a. the difference between the population means. b. the sample size. c. the sample standard deviation. d. the shape of the distribution.
the sample size.
A statistically significant outcome is one that has a small likelihood of occurring if the null hypothesis is: A) wrong. B) true. C) false. D) accepted.
true.
It is important to think about power because: a. everyone uses it. b. we don't want to run experiments that have little chance of finding something. c. it is likely to guarantee successful studies. d. none of these.
we don't want to run experiments that have little chance of finding something.
Cohen's d-hat is an example of: a. a measure of correlation. b. an r-family measure. c. a d-family measure. d. a correlational measure.
A d-family measure
Which of the following designs is used when the researcher focuses on the way behavior changes with the systematic introduction and withdrawal of the treatment? A) successive treatment design B) ABAB design C) multiple baseline design D) case study
ABAB design
Which of the following is involved in the calculation of power? a. alpha () b. the standard deviation c. the difference between the means d. All of these are involved.
All of these are involved.
Which of the following is NOT part of the Central Limit Theorem? a. The mean of the sampling distribution approaches the population mean. b. The variance of the sampling distribution approaches the population variance divided by the sample size. c. The sampling distribution will approach a normal distribution as the sample size increases. d. All of these are part of the Central Limit Theorem.
All of these are part of the central limit theorem
Which of the following statistics comparing a sample mean to a population mean is most likely to be significant if you used a two-tailed test? a. t = 10.6 b. t = 0.9 c. t = -10.6 d. both t = 10.6 and t = -10.6
Both t = 10.6 and t = -10.6
Which of the following is sometimes a serious problem with repeated measures designs? a. Carryover effects can cloud the interpretation. b. Small sample sizes can distort the results more than with other designs. c. They require more subjects than designs with independent samples. d. All of these.
Carryover effects can cloud the interpretation
Which of the following is not an advantage of the case study method? A) Case studies provide a rich source of insights into possible causes of people's behavior. B) Case studies can provide useful evidence to support or challenge psychological theories. C) Case studies provide an opportunity to "try out" new therapeutic techniques. D) Case studies are especially useful for studying events that occur frequently.
Case studies are especially useful for studying events that occur frequently.
In one-sample tests of means we: a. compare one sample mean with another. b. compare one sample mean against a population mean. c. compare two sample means with each other. d. compare a set of population means.
Compare one sample mean against a population mean
The point of calculating effect size measures is to: a. decide if something is statistically significant. b. convey useful information to the reader about what you found. c. reject the null hypothesis. d. prove causality.
Convey useful information to the reader about what you found
For a t test with one sample we: a. lose one degree of freedom because we have a sample. b. lose one degree of freedom because we estimate the population mean. c. lose two degrees of freedom because of the mean and the standard deviation. d. have N degrees of freedom.
Lose one degree of freedom because we estimate the population mean
The variance of an individual sample is more likely than not to be: a. larger than the corresponding population variance. b. smaller than the corresponding population variance. c. the same as the population variance. d. less than the population mean.
Smaller than the corresponding population variance
The term "effect size" refers to: a. how large the resulting t statistic is. b. the size of the p value, or probability associated with that t. c. the actual magnitude of the mean or difference between means. d. the value of the null hypothesis.
The actual magnitude of the mean or difference between means
Which of the following statements concerning the external validity of single-subject experiments is false? A) Evidence for the external validity treatment effects can be established when researchers use the procedures of single-subject designs with a small group of individuals. B) Evidence for the external validity of treatment effects can be established from the use of multiple-baseline designs. C) The external validity of single-subject experiments can be established because the single-subject design tests several independent variables simultaneously. D) The external validity of single-subject experiments is likely enhanced because the types of interventions in these experiments frequently produce sizable changes in behavior.
The external validity of single-subject experiments can be established because the single-subject design tests several independent variables simultaneously.
If we have run a t test with 35 observations and have found a t of 3.60, which is significant at the .05 level, we would write: a. t(35) = 3.60, p <.05 b. t(34) = 3.60, p >.05 c. t(34) = 3.60, p <.05 d. t(35) = 3.60, p <05
t(34) = 3.60, p <.05
All other things being equal, one study will have more power than another study if: a. it has more subjects. b. it controls error variance better. c. it compares groups that are more extreme. d. all of these.
all of these.
A weighted average is a. the average of two weights. b. an average that gives greater influence to the larger sample. c. an average that reduces the influence of the larger sample. d. the balance between the sample size and the mean.
an average that gives greater influence to the larger sample.
The smaller the exact probability associated with results of NHST, the greater is the probability that: A) an exact replication will produce a statistically significant finding at p < .05. B) we have made a Type I error. C) we have made a Type II error. D) the results will have practical significance.
an exact replication will produce a statistically significant finding at p < .05.
A researcher who wishes to determine whether a treatment increases the frequency of a behavior will have the most difficulty interpreting the outcome of a single-subject experiment if the baseline stage demonstrates: A) a stable pattern for the behavior. B) a decreasing trend for the behavior. C) an increasing trend for the behavior. D) All of these
an increasing trend for the behaviour
A simple main effects analysis examines the effect of one independent variable: A) across all levels of another independent variable. B) in a single factor design. C) at one level of a second independent variable. D) for all other independent variables.
at one level of a second independent variable.
When conducting an analysis of variance, we assume that any systematic variation due to the effect of the independent variable is added to: A) within-group variation. B) between-group variation. C) the denominator of the F ratio. D) the null hypothesis.
between-group variation.
A t test, in general, involves: a. dividing the difference between means by the standard deviation of the population. b. dividing the difference between means by the standard deviation of the sample. c. dividing the difference between means by the standard error of a distribution of differences between means. d. dividing the difference in standard deviations by the size of the larger mean.
dividing the difference between means by the standard error of a distribution of differences between means.
Researchers are often unable to control extraneous variables when they use the case study method. This lesser degree of control makes it difficult to use the case study method to: A) draw cause-effect conclusions about behavior. B) develop predictions of behavior. C) consider alternative theoretical explanations of behavior. D) develop descriptions of behavior.
draw cause-effect conclusions about behavior.
In an analysis of variance for repeated measures the systematic variation due to participants is: A) combined with between-group variation. B) eliminated from the analysis. C) combined with residual variation. D) added to the denominator of the F ratio.
eliminated from the analysis.
A Type II error arises when we: A) reject a true null hypothesis. B) accept a true null hypothesis. C) fail to reject a false null hypothesis. D) fail to accept a true null hypothesis.
fail to reject a false null hypothesis.
A researcher was interested in examining the different levels of aggression shown by college students and prisoners with life sentences. Aggression was measured by surveys given during one session. Which analysis should the researcher perform on the mean aggression scores of the groups? a. related means t test b. independent means t test c. correlation d. regression
independent means t test
In a multiple-baseline design, the target behavior should change: A) just before the onset of the treatment. B) long before the onset of the treatment. C) just after the onset of the treatment. D) long after the onset of the treatment.
just after the onset of the treatment.
Which of the following issues deserves special consideration when researchers choose to use the ABAB design? A) justification for withdrawing a potentially beneficial treatment B) change in behavior prior to the end of the baseline stage C) excessive variability of the baseline in single-case experimental designs D) limited external validity of single-case experimental designs
justification for withdrawing a potentially beneficial treatment
Which of the following patterns represents an ideal baseline in a single-subject experimental design? A) line with a positive slope (diagonal from lower left to upper right) B) line with zero slope (horizontal line) C) line with a negative slope (diagonal from upper left to lower right) D) jagged line with several peaks and valleys
line with zero slope (horizontal line)
When presented by the media, positive results for the effects of treatment observed in a case study: A) are typically presented in conjunction with the limitations of the study. B) may prevent people from seeking out treatments shown to be effective in more controlled research. C) may prevent researchers from investigating the treatment further. D) are shown to have limited generality—that is, the beneficial effects likely won't occur for other people.
may prevent people from seeking out treatments shown to be effective in more controlled research.
Which of the following is not one of the disadvantages of the case study method? A) difficulty in drawing cause-and-effect conclusions B) bias can arise due to distortions in patient's self-reports C) poor source of hypotheses about behavior D) difficult to generalize from a single case
poor source of hypotheses about behaviour
What do each of the multiple baselines in the multiple-baseline single-case experimental design represent? A) individual case studies B) replications built into the design C) redundant sources of evidence D) inevitable sources of confounding
replications built into the design
Which of the following is not an acceptable approach to dealing with the problem of excessive baseline variability? A) seeking out and removing sources of variability B) selecting only the last data point in the baseline for analysis C) extending the time during which baseline observations are made D) averaging data points to remove the "appearance" of variability
selecting only the last data point in the baseline for analysis
The likelihood that an experiment will detect the effect of an independent variable when the independent variable really had an effect refers to an experiment's: A) level of significance. B) alpha. C) significance. D) sensitivity.
sensitivity.
A research outcome that leads us to reject the null hypothesis is said to be: A) statistically nonsignificant. B) statistically inconsequential. C) statistically significant. D) statistically likely.
statistically significant.
When calculating eta squared for a two factor design, eta squared is equal to the sum of squares for the effect of interest divided by the sum of squares for the effect of interest and the: A) sum of squares between. B) sum of squares within. C) sum of squares total. D) sum of squares within plus between.
sum of squares within.
In addressing the problem of the limited external validity of single-case research, it's safe to assume that: A) single-case research designs always have poor external validity. B) we can never generalize the results for a single individual or small group of individuals to a larger population. C) treatment effects in single-case research tend to be small and poor in generality. D) the ability to generalize from a single case depends on the degree of variability in the population from which the case was selected.
the ability to generalize from a single case depends on the degree of variability in the population from which the case was selected.
The example of the moon illusion discussed in the text illustrates the fact that: a. the best estimate of the size of an effect need not use the standard deviation. b. standardized effect sizes are clearly superior. c. the moon grows as it rises in the sky. d. an effect size is best based on medians.
the best estimate of the size of an effect need not use the standard deviation.
Cohen's d-hat refers to: a. the probability associated with t. b. the difference between the means before and after treatment. c. the "diagnostic" statistic. d. the difference between the means before and after treatment divided by a standard deviation.
the difference between the means before and after treatment divided by a standard deviation.
The 2-tailed significance level tells us: a. the difference is not significant at the .05 level. b. the difference is significant at the .05 level. c. the means of the pre- and post-scores are large. d. We can't tell whether the difference is significant or not.
the difference is not significant at the .05 level
In the test on the treatment of anorexia, the resulting t was -3.22, which was significant (p < .05). This tells us that: a. the family therapy condition had a mean that was reliably less than the mean of the control condition. b. the family therapy condition had a mean that was reliably more than the mean of the control condition. c. the family therapy condition had a mean that was unreliably less than the mean of the control condition. d. the family therapy condition had a mean that was unreliably more than the mean of the control condition.
the family therapy condition had a mean that was reliably more than the mean of the control condition.
The null hypothesis in a repeated measures t test is: a. the hypothesis that the mean difference score is equal to 0. b. the hypothesis that the mean difference score is different from 0 in either direction. c. the hypothesis that post scores are larger than pre-scores. d. the hypothesis that the variance of scores stays constant from pretest to posttest.
the hypothesis that the mean difference score is equal to 0.
When testing the means of independent samples, the null hypothesis is best thought of as: a. the mean of population 1 is equal to the mean of population 2. b. the mean of population 1 is unequal to the mean of population 2. c. the mean of a set of difference scores is equal to 0. d. the two population means don't differ by more than 10 points.
the mean of population 1 is equal to the mean of population 2.
A mixed design is a complex design where one independent variable represents an independent groups design (random groups or natural groups) and another independent variable represents: A) the repeated measures design. B) a variable with only two levels. C) a variable with more than three levels. D) the correlational design.
the repeated measures design.
The effect size can best be thought of as: a. the size of the largest mean. b. the size of the difference between means in standard deviation units. c. a mixture of the size of the difference and the sample size. d. the largest difference we would hope to find.
the size of the difference between means in standard deviation units.
For a very conservative test when we don't pool the variances we should: a. work at = .01 instead of = .05. b. insist that the critical value of t be twice the tabled value. c. use a much reduced number of degrees of freedom. d. throw up our hands and call the problem too difficult.
use a much reduced number of degrees of freedom.
The null hypothesis of a related scores t test is: a. µD = µ1 - µ2 = 0 b. µ1 = µ2 = µD + 1 c. µ1 = 0 d. µD = µ2
µD = µ1 - µ2 = 0
