36 credit card holders are selected at random. For each, their current credit card balance is recorded. The average for these 36 people is = $600. Assume that the current balance of all credit card holders follows a normal distribution with unknown mean u, and that a 85.3% condence interval for [J is found to be $600 in 30.9. Find the standard deviation 0 of the population? D_l_-.l._..l A._....._... 4'37 Od