population mean from sample?

Question

A random sample of 49 observations is taken from a normal population with a variance of 100. The sample mean is 25 . Find the unbiased estimate of the population mean

Answer 1

N=49, pop is normal with var = 100 and pop standard deviation = 10

x bar = 25= unbiased point estimate of the population mean

CI = 25 +/- about zsd/sqrN = 25+/- 2(10)/5 = 25+/-4

= (21, 29)