What is the Null hypothesis?

Question

A researcher claims that 20-year old women on a special diet will have an average weight of less than 125 lbs. A sample of 9 women has the following weight (in lbs): 110, 108, 114, 95, 102, 98, 111, 125, 118. At 5% level of significance, can you agree to the claim?

Null hypothesis

A. Ho: μ ≤ 109

B. Ho: μ ≥ 125

C. Ho: μ = 125

D. Ho: μ = 109 Ho: μ ≤ 3 C. Ho: μ = 3 D. Ho: μ ≥ 3

Answer 1

The Null Hypothesis is, essentially, the hypothesis that states nothing has changed...what we thought was true is still true. In this scenario, it would be that Ho: μ = 125 because that is the weight the researcher is using to compare the women on the special diet to.

Another way to look at things is that the null hypothesis states what would be the case without any special treatment. Basically, it says that these women would have a mean weight of 125Lbs WITHOUT being on the special diet. With the special diet (the alternate hypothesis) they will weigh, on average, Less than 125 lbs