A group of 12 subjects are weighed at day one of a weight re

A group of 12 subjects are weighed at day one of a weight reducing clinic and again at day 7, resulting in a total of 24 measurements. The research question is: Has any significant weight been lost during this week? Please provide the Ho, Ha, df and the test you would use.

Solution

Let

u1 = weight at day 1
u2 = weight at day 2

Thus,

Ho: u2 - u1 >= 0
Ha: u2 - u1 < 0 [ANSWER, HYPOTHESES]

We will use a PAIRED T TEST HERE, as there is natural pairing between the two groups, as they came form the same people. [answer, TEST]

Here, df = n - 1 = 12 - 1 = 11. [ANSWER, DF]