In: Math
When 41 people are used the Weight Watchers diet for one year, their weight losses had a standard deviation of 4.9lb. Use a 0.01 significance level to test the claim that the amounts of weight loss have a standard deviation equal to 6.0lb, which appears to be the standard deviation for the amounts of weight loss with the Zone diet. Write your assumptions before you conduct hypothesis testing.
Answer:
Given,
Null hypothesis Ho : = 6
Alternative hypothesis Ha : 6
Now test statistic = (n - 1)s^2 / ^2
substitute values
= (41- 1)*4.9^2 / 6^2
= 40*4.9^2 / 36
test statistic = 26.68
Now to give the critical value for test statistic
40,0.995 = 20.707
40,0.005 = 66.766
P( > 20.707) = 0.995
P( > 66.766) = 0.005
Since the test statistic is 26.68 is between than critical values , thus the Ho is not rejected at 0.01 significance level.
Here we claim that the amount of weight loss have = 6 which is same as of zone diet which seems to be valid.