In: Statistics and Probability
In a study, 272 moderately obese subjects were randomly assigned to one of three diets: low-fat, restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, nonrestricted-calorie. The prediction was that subjects on a low-carbohydrate diet would lose weight, on the average. After two years, the mean weight loss was 5.5 kg for the 109 subjects in the low-carbohydrate group with a standard deviation of 7.0 kg. The technology output below shows results of a significance test for testing
Upper H 0 : mu equals 0H0: μ=0
against
Upper H Subscript a Baseline : mu not equals 0Ha: μ≠0,
where
muμ
is the population mean weight change. Note that weight change is determined by calculating after
weightminus−before
weight. Complete parts a through c below.
N |
Mean |
StDev |
SE Mean |
95% CI |
T |
P |
109 |
minus−5.500 |
7.000 |
0.670 |
(minus−6.829,minus−4.171) |
minus−8.20 |
0.000 |
a. Identify the P-value for this test.
The P-value is (Type an integer or a decimal. Do not round.)
b. How is the P-value interpreted?
A. The P-value is the probability of observing a sample mean weight change (loss or gain) of 5.5 kg or more if the null hypothesis is true.
B. The P-value is the probability of observing a sample mean weight loss of exactly 5.5 kg if the null hypothesis is true.
C. The P-value is the probability of observing a sample mean weight change (loss or gain) of exactly 5.5 kg if the null hypothesis is true.
c. Would the P-value and 95% confidence interval lead to the same conclusion about H0? Explain.
The 95% confidence interval is (fill in) which (fill in) the hypothesized value for the mean, so (fill in) H0. The P-value is (fill in) than a significance level of 0.05, so (fill in) H0.
So, the P-value and 95% confidence interval (fill in) to the same conclusion about H0.