Question 1

A new company has made the claim that its test preparation program will improve SAT scores by 25 points.A skeptical educational psychologist has decided to test this theory and has enlisted 25 students who are willing to participate in the program.Assume the standard SAT mean is 550 with a standard deviation of 100.
a.What is the predicted effect size for an increase of 25 points?
b.Explain the logic of what has been done.
c.Advanced topic: Sketch the distributions involved.
d.Advanced topic: If the data are analyzed at the .05 significance level,what will be the power of the study?
e.Advanced topic: Explain your answer to a person who understands hypothesis testing with means of samples,but who is not familiar with power.

Accepted Answer

The answer of A new company has made the claim...

Question 2

Interpreting the results of theoretical studies is more likely to emphasize significance level,while interpreting the results of applied studies is more likely to emphasize __________.

Accepted Answer

The answer of Interpreting the results of theoretical studies is...

Question 3

Advanced topic: A social psychologist is designing a study to see whether people who see a particular film are more likely to use violence as a solution to a problem.The psychologist plans to use a scale that assesses this construct,which has a population mean of 78 and a standard deviation of 14.The psychologist expects an increase of eight points above the population mean.Fifteen participants will be enrolled in the study,and the data will be analyzed at the .05 level.
a.What is the power of the study?
b.Sketch the distributions involved.
c.Explain your answer to a person who understands hypothesis testing with means of samples,but who is not familiar with effect size or power.
d.What is the predicted effect size?
e.What are three things that might be done to increase the power of the study?

Accepted Answer

The answer of Advanced topic: A social psychologist is designing...

Question 4

The smaller the population standard deviation,the greater the power,because the distributions of means based on the known and comparison populations are both __________.

Accepted Answer

The answer of The smaller the population standard deviation,the greater...

Question 5

A researcher obtains a statistically significant result.However,if he used a large sample,then the result may not __________.

Accepted Answer

The answer of A researcher obtains a statistically significant result.However,if...

Question 6

An organizational psychologist conducted a study to see whether upgrading a company's older computer system to newly released,faster machines would cause an increase in productivity from the current average of 120 units with a standard deviation of 20.The new system will be tested in a single department with 45 employees.The company has decided that an increase of less than 10 units will not justify purchasing the new system.
a.What is the predicted effect size for an increase of 10 points?
b.Explain the logic of what has been done.
c.Advanced topic: Sketch the distributions involved.
d.Advanced topic: If the data are analyzed at the .01 significance level,what will be the power of the study?
e.Advanced topic: Explain your answer to a person who understands hypothesis testing with means of samples,but who is not familiar with power.

Accepted Answer

The answer of An organizational psychologist conducted a study to...

Question 7

Advanced topic: A psychologist investigating hearing thresholds knows that an average participant gets a score of 42 with a standard deviation of 15 on a standard hearing test.The psychologist plans to add a distraction task to the standard test for 10 participants and evaluate the effect of the distraction at the .01 level.The psychologist believes that the distraction should result in a 12-point reduction in scores .During the planning process,the psychologist realizes that 10 participants may not be enough for adequate power and has asked a consultant to calculate the power for this experiment.
a.What is the current power of the planned study?
b.Sketch the distributions involved.
c.What are three ways to increase the power of this study?
d.What is the predicted effect size?
e.Explain these procedures to a person who understands hypothesis testing with means of samples,but who is not familiar with effect size or power.

Accepted Answer

The answer of Advanced topic: A psychologist investigating hearing thresholds...

Question 8

A study in which the results are not sufficient to reject the null hypothesis is truly inconclusive if the __________ is low.

Accepted Answer

The answer of A study in which the results are...

Question 9

In studies using a very large number of participants,it is common to get statistically significant results that have a very small __________.

Accepted Answer

The answer of In studies using a very large number...

Quiz 6: Making Sense of Statistical Significance:decision Errors, Effect Size, and Statistical Power

Interpreting the results of theoretical studies is more likely to emphasize significance level,while interpreting the results of applied studies is more likely to emphasize __________.

The smaller the population standard deviation,the greater the power,because the distributions of means based on the known and comparison populations are both __________.

A researcher obtains a statistically significant result.However,if he used a large sample,then the result may not __________.

A study in which the results are not sufficient to reject the null hypothesis is truly inconclusive if the __________ is low.

In studies using a very large number of participants,it is common to get statistically significant results that have a very small __________.