A random sample of size 15 is taken from a normally distributed population with a sample mean of 75 and a sample variance of 25. The upper limit of a 95% confidence interval for the population mean is equal to ____.
A)	77.530
B)	72.231
C)	74.727
D)	79.273
Answer:A
A random sample of size 15 is taken from a normally distributed population with a sample mean of 75 and a sample variance of 25. The upper limit of a 95% confidence interval for the population mean is equal to ____.
A)	77.530 B)	72.231 C)	74.727 D)	79.273