Suppose a 98% confidence interval for the population mean (u) turns out to be [lower bound, upper bound]. If this interval was based on a sample size of 22, explain what assumptions are necessary for this interval to be valid.
a) The population of salaries must have an approximate t-distribution.
b) The population must have an approximately normal distribution.
c) The sampling distribution of the sample mean must have a normal distribution.
d) The sampling distribution must be unbiased with 21 degrees of freedom.