Question

1. Suppose that X 1 , X 2 and X 3 are i.i.d (i.e. independent and identically distributed) random
variables each with mean and variance . Which of the following three point estimators of is the “best”
point estimator? Justify your answer.

2.The mean annual salary for flight attendants is about $65,700 and the standard deviation is
$14,500. A random sample of 100 flight attendants is selected from this population.
What is the probability that the mean annual salary of the sample is
a) less than $64,250

b) greater than $69,470
c) between $64,250 and $67,875
d) Find the third quartile of the sampling distribution of the man annual salaries.

Answer 1