Sunlight makes everyone feel better.. To test this claim, 30 ...

[skymedlock]

Sunlight makes everyone feel better.. To test this claim, 30 college students receive special lights for their bedrooms that slowly turn on in the morning with imitation sunlight. The experiment takes place in January, when it is still dark out in the morning. Prior to participation, the students fill out a questionnaire to measure their general mood. The average score was 2.73 . After three weeks with the special light they fill in the questionnaire again. The average score this time was 3.13 . The standard deviation of the differences was 0.822 . Calculate a 95 confidence interval for the difference in average mood scores (after  before).
 a. (0.14, 0.66)
  b. (0.09, 0.71)
  c. (0.19, 0.61)
  d. None of the above

Question 2

In each situation, indicate whether it would make more sense to find a confidence interval for the population parameter or to conduct a hypothesis test for a specific null value. If your answer is a hypothesis test, specify the null value that you would test. A high school teacher is interested to know if students who take a foreign language will get higher grades if their final exam is an oral exam instead of a written exam. The following year he asks all of the Spanish teachers to give their students an oral exam at the end of the course. The average exam score in the previous years was 68 (out of a possible 100 points).

[samiel-sayed]

Answer to Question 1

B

Answer to Question 2

Hypothesis test; the null value would be a mean score of 68 .

[skymedlock]

Wow, this really help

[jackie]

Gracias!