Which of the following is an unbiased estimator for the corresponding parameter?
a.The population standard deviation
is an unbiased estimator for the sample standard deviation
s.
b.The sample mean
is an unbiased estimator for the population mean
.
c.The population proportion is an unbiased estimator for the sample proportion.
d.The population variance
is an unbiased estimator for the sample variance
s2.
Question 2 Suppose the income of recent doctoral graduates who become professors at a university is approximately normally distributed with a mean income of 42,000 and a standard deviation of 8000. If a random sample of size 100 is taken and the mean
is calculated, what is the probability that this mean value will be between 43,500 and 45,000?
a.0.072
b.0.0309
c.0.9999
d.0.969
