Study report 83% are using credit cards. random sel. 50 students and 40 use credit cards. a=0.04 is

For a certain year a study reports that the % of colleges students using credit cards was *=83%. A college dean of students services feel that this is to high for her university, so she randomly selects 50 students and finds that 40 of them use credit cards. at a=0.04, is she correct about her university?

and how do i work this out. and what table do i use.

Study report 83% are using credit cards. random sel. 50 students and 40 use credit cards. a=0.04 is this corre

You need to run a hypothesis test (left tailed) on the population proportion:

Ho: proportion = .83

Ha: proportion %26lt; .83

The test statistic is:

(.83 - .80) / ((.80*.20)/50) = .53033

This follows the standard normal distribution. Here is a table

http://www.castleton.edu/math/statistics...

This site also might help you:

http://www.ltcconline.net/greenl/courses...

As you can see, this is not significant at the .04 significance level. Therefore, based on this sample the answer is %26quot;no%26quot; the dean is not correct in saying that less than 83% of her college students use credit cards.

Stated formally: we do not find sufficient evidence to support the claim that the proportion of college students using credit cards at this university is less than 83%.

Good Luck~