at a high school debate tournament, half of the teams were asked to wear suits and ties and the rest were asked to wear jeans and t- shirts. The results are given in th etable below. In order to test the claim at the 0.05 level that the proportion of win is the same for teams wearing sutis as for the teams wearing the jeans, what would the null hypothesis be?

A) The proportions of wins is the same for teams wearing suits as for teams wearing jeans
B) The proportions of wins is the different for teams wearing suits as for teams wearing jeans
C) The mean number of wins is the same for teams wearing suits as for teams wearing jeans
D) The mean number of wins is the same for teams wearing suits as for teams wearing jeans

Although the question says that they will "test the claim at the 0.05 level that the proportion of win is the same for teams wearing sutis as for the teams wearing the jeans", the claim, that will be expressed in the alternative hypothesis, is that there is a significant difference between the two proportions.

The null hypothesis, the one that this test try to nullify, will state that there is no significant difference between the two proportions. Or, saying the same, that the proportions are equal.

The right answer is A, which states that the two proportions (as this is a test on the difference of proportions) are equal.