Session 9 Quizziz

Practice: When to Use Which Test? 

A team of psychologists are interested in the effects of sleep deprivation on new learning. College students (N = 20) stay in a sleep lab for 2 days. Ten participants are randomly assigned to an experimental condition in which they are not permitted to sleep during that period; the other ten participants are allowed to sleep when they wish.  

At the end of two days, all participants attended a class that taught the principles of gene combination. They were given a test after the end of the class.  

 

Q1. Which of the following statements is true about the design? 

• There is only one group of students, but two experimental conditions. 

• There are two independent groups of students: sleep deprived and not sleep deprived. 

• The groups of students in the design are correlated. 

• There are two independent groups of students: good learners and poor learners

A team of psychologists are interested in the effects of sleep deprivation on new learning. College students (N = 20) stay in a sleep lab for 2 days. Ten participants are randomly assigned to an experimental condition in which they are not permitted to sleep during that period; the other ten participants are allowed to sleep when they wish.  

 

At the end of two days, all participants attended a class that taught the principles of gene combination. They were given a test after the end of the class.  

Q2. At the end of two days, all participants attended a class that taught principles of gene combination. They were given a long test after the end of the class and counted the number of correct answers. Which of the following statistics would you recommend to test their hypothesis? 

• A t-test for independent means 

• A Chi-square test of independence

• A McNemar test

• A t-test for dependent means (paired)

TRUE OR FALSE: The meaning of the p-values for independent sample t-tests are the same as for Chi-square tests: the probability of obtaining a test statistic of that size or greater if, in the population, the null hypothesis holds true.

• TRUE

• FALSE

Check out the p-value for the t-test (yellow).  What's your conclusion?

• Reject the null, conclude the mean knowledge score is significantly different between the pre and the post.

• Do not reject the null.  The mean score at post-intervention is the same as baseline (ie, the mean difference is 0).

Check out the two values in the top table (green).  What's your conclusion?

• The mean knowledge score stayed the same

• The mean knowledge score decreased significantly from 5.55 to 4.22

• 
  The mean knowledge score increased significantly from 4.22 to 5.55

What do you think the 1.331 in aqua represents?

• It's about the standard deviations

• It's the mean difference between post and pre (5.55-4.22)

• it's about the t-statistic

The McNemar test is another test for...

• Non-independent (paired samples)

• Independent samples