Ophelia O'Brien, VP of Consumer Credit of American First Banks $($AFB$),$ monitors the default rate on personal loans at the AFB

member banks. One of her standards is $"$no more than $5\%$ of personal loans should be in default." On each Friday, the default rate is

calculated for a sample of $500$ personal loans. Last Friday's sample contained $30$ defaulted loans. Using $a=0\mathrm{.}10,$ the appropriate

decision is to

reject the null hypothesis

reduce the sample size

do nothing

increase the sample size

fail to reject the null hypothesis