4. In order to investigate the relationship between employment status at the time a loan was arranged and whether or not the loan is now in default, a loan company manager randomly chooses 100 accounts, with the results indicated below.

Present status of loan	Employment status at time of loan
Employed	Unemployed	Total
In default	10	8	18
Not in default	60	22	82
Total	70	30	100

a) Test the null hypothesis that employment status and status of the loan are independent variables, using

the 5 percent level of significance for the test.

b) Test that the proportion of employed in default is equal to the proportion of unemployed in default. Use