PSYC 354 CH 8 EXAM QUESTIONS AND
ANSWERS 100% SOLVED
Imagine that a study of memory and aging finds that younger participants correctly recall
55% of studied words, older participants correctly recall 42% of studied words, and the size of
this effect is Cohen's d = 0.49. This effect size indicates that the memory performance of: -
ANSWER older participants is approximately half a standard deviation below that of younger
participants.
A researcher interested in the effects of humor on memory randomly assigns 16 participants
to either the humor group or the no-humor group. The humor group reads humorous
sentences and the no-humor group reads non-humorous sentences. On a later memory test,
the researcher finds that in terms of the direction of the means, the humor group had better
memory than the no-humor group, but this effect was not significant (p = 0.06). What might
you recommend that this researcher do? - ANSWER Because the effect looks as though it is
barely missing significance, and her sample size is fairly small, she can increase her sample
size to increase her power to detect the effect.
An article in the journal Applied Nutritional Investigation reported the results of a comparison
between a low-calorie soy-protein diet and a low-calorie traditional-protein diet (Liao, 2007).
Twelve obese participants were randomly assigned to each diet. At the end of the diet period,
those on the soy diet lost an average of 2.3% of their body fat (SD = 0.55), while those on the
traditional diet lost an average of 1.22% of their body fat (SD = 0.50). If we increase the
sample size of this study, the value of the test statistic would ________ but the effect size would
________. - ANSWER increase; remain the same
, What is the probability we will not make a Type II error? - ANSWER statistical power.
When considering the results from an opinion poll, where several verbal expressions are rated
for their level of annoyance, what is particularly useful about margins of error is that: -
ANSWER we can figure out more than one interval estimate for the same poll to see if they
overlap.
If you have less than a(n) ________ chance of rejecting the null hypothesis when it is false, you
have insufficient power. - ANSWER 80%
Power can be calculated before the study in order to determine the ideal sample size, and in
this case it is known as a(n): - ANSWER a priori test
If an effect is significant but the effect size for the difference between the two means is small
(according to Cohen's conventions), about how much overlap will there be between the two
distributions? - ANSWER 85%
Which of the following accurately captures the difference between a confidence interval and
confidence level? - ANSWER The confidence interval is the range of scores around the mean
about which we have a level of confidence.
A confidence interval is a(n) ________ that includes the population mean after repeatedly
sampling. - ANSWER interval estimate
ANSWERS 100% SOLVED
Imagine that a study of memory and aging finds that younger participants correctly recall
55% of studied words, older participants correctly recall 42% of studied words, and the size of
this effect is Cohen's d = 0.49. This effect size indicates that the memory performance of: -
ANSWER older participants is approximately half a standard deviation below that of younger
participants.
A researcher interested in the effects of humor on memory randomly assigns 16 participants
to either the humor group or the no-humor group. The humor group reads humorous
sentences and the no-humor group reads non-humorous sentences. On a later memory test,
the researcher finds that in terms of the direction of the means, the humor group had better
memory than the no-humor group, but this effect was not significant (p = 0.06). What might
you recommend that this researcher do? - ANSWER Because the effect looks as though it is
barely missing significance, and her sample size is fairly small, she can increase her sample
size to increase her power to detect the effect.
An article in the journal Applied Nutritional Investigation reported the results of a comparison
between a low-calorie soy-protein diet and a low-calorie traditional-protein diet (Liao, 2007).
Twelve obese participants were randomly assigned to each diet. At the end of the diet period,
those on the soy diet lost an average of 2.3% of their body fat (SD = 0.55), while those on the
traditional diet lost an average of 1.22% of their body fat (SD = 0.50). If we increase the
sample size of this study, the value of the test statistic would ________ but the effect size would
________. - ANSWER increase; remain the same
, What is the probability we will not make a Type II error? - ANSWER statistical power.
When considering the results from an opinion poll, where several verbal expressions are rated
for their level of annoyance, what is particularly useful about margins of error is that: -
ANSWER we can figure out more than one interval estimate for the same poll to see if they
overlap.
If you have less than a(n) ________ chance of rejecting the null hypothesis when it is false, you
have insufficient power. - ANSWER 80%
Power can be calculated before the study in order to determine the ideal sample size, and in
this case it is known as a(n): - ANSWER a priori test
If an effect is significant but the effect size for the difference between the two means is small
(according to Cohen's conventions), about how much overlap will there be between the two
distributions? - ANSWER 85%
Which of the following accurately captures the difference between a confidence interval and
confidence level? - ANSWER The confidence interval is the range of scores around the mean
about which we have a level of confidence.
A confidence interval is a(n) ________ that includes the population mean after repeatedly
sampling. - ANSWER interval estimate
