A physics instructor believes natural light improves learnin

A physics instructor believes natural light improves learning and randomly assigns a total of 50 students to a natural light condition (n=25) or an artificial light condition (n=25). Both groups receive a learning task and are given a test scored as number correct. What condition below will you assess for the appropriate statistical test for this study?

   a.   Do the groups have similar standard deviations?

   b.   Are the scores normally distributed in each condition?

   c.   Does the relationship appear linear?

   d.   Is the sample randomly selected?

Solution

H₀: Mean(Natural light)>Mean(Artificial Light)

H_A: Mean(Natural Light)<=Mean(Artificial Light)

As we need to investigate the relationship between the means, and population variance is not known, we will use the t distribution

a. Will not be appropriate as similar standard deviations does not lead to a conclusive result. We may have similar standard deviations for either of the cases.

b. Will be appropriate as the condition we need to test is for the mean score, therefore the distribution needs to be normal, since n(=25) is less.

c. Will not be appropriate as we need to note the difference between the test scores of the two samples.

d. Will not be appropriate as the assignment is random from the entire population available.