The amount of money spent upon food per week by American Family is known to have the mean of $92 and standard deviation of $9. Assume a random sample of 81 families is taken and their sample mean food expenditure is calculated.
a) Explain the sampling distribution of the sample mean.
b) Determine the probability that the sample mean does not exceed $91.
c) Determine the probability that the sample mean is more than $94.
d) Determine the probability that the sample mean lies within $2 of the population mean.