A population of 1000 students spends an average of $10.50 a day on dinner. the standard deviation of the expenditure is $3. A simple random sample of 64 students is taken. a) what are the expected value, standard deviation and shape of the sample mean? b) What is the probability that these 64 students will spend a combined total of more than $712.21? C) What is the probability that these 64 students will spend a combined total between 703.59 and $728.45?