Question

1. Does reading on a light-emitting e-reader at bedtime increase how long it takes to fall asleep? A sample of 12 healthy adults slept in the lab on two different nights. In random order, subjects read for 30 minutes in a print book one night and with a light-emitting e-reader the other night. Scalp electrodes were used to measure how long (in minutes) it took subjects to reach a deep sleep stage. The researchers compared the difference in the amount of time it took the person to reach deep sleep.

a. Which type of test is appropriate, a two sample t-test or a matched pairs t-test. Briefly explain why.

b. State the hypotheses for their test.

2. A study compared tooth health in a group of 46 young adult males with a tongue piercing and a control group of 46 young adult males without tongue piercing. The study wanted to determine if the mean number of enamel cracks for those with a tongue piercing was greater than the mean number for those without.

a. Which type of test is appropriate, a two sample t-test or a matched pairs t-test. Briefly explain why.

b. State the null and alternative hypotheses. STAT 101

c. The test resulted in a P-value of 0.0013. At a 5% significance level, what conclusion should me made?

3. A study of whether or not customers respond to odors took place in a small pizza restaurant in France on two Saturday evenings in May. On one of these evenings, a relaxing lavender odor was spread through the restaurant. On the other evening, no scent was used. The restaurant owners computed the mean amount spent on each night and computed a 95% confidence interval for the difference of means (lavender minus no odor) in Euros to be (2.40, 4.82). Can the researchers conclude there is a difference between the two means?

Answer 1

use a Here we matched pairs t-test because the sample observations are not completely independent but they are dependent in pairs Suppose di, H2.... Raiz be the observation where the 12 healthy adults slept in slept in the lab without light emitting e-reader and yi Ya Liz the observations where the 12 healthy adults slept in the lab with light emitting e-reader. pairs of observations (8 7) (P2, L2), ($12, 212) correspond to the ist and unit respectively Here instead of applying the test for significance of difference of the means we apply the test for significance of mean or difference we called it matched t-test. 12th pair 12 let die Hi-Li 1-2 denote the difference the observation for for ith unit Here we have to test the null hypothesis 6 Ho: 41-42 = 30 Ho: (Hd) = 30 ie The increment are just by 30 minutes. VS Hi : ud L 30 The reading on a light emitting e-reader at bedtime increase to fall sleep 4 - The mean of healthy adults without light N2 = The mean of healthy adults with light emitting e-reader CS Scanned with CamScanner