Incomes in a certain town are strongly right skewed with mea

Incomes in a certain town are strongly right skewed with mean $36,000 and standard deviation $7000. A random sample of 75 households is taken. What is the probability the sample mean is greater than $37,000? (Use Table A)

A. .4432

B. .1075

C. 0

Solution

Incomes in a certain town are strongly right skewed with mean $36,000 and standard deviation $7000. A random sample of 75 households is taken. What is the probability the sample mean is greater than $37,000? (Use Table A)

A. .4432

B. .1075

C. 0

Standard error = 7000/sqrt(75) =808.29

Z value for 37000, ( 37000-36000)/808.29 = 1.24

P( meanx >37000)= P( z >1.24) = 0.1075

Correct answer = B 0.1075