Question

Suppose a subdivision on the southwest side of Denver, Colorado, contains 1,500 houses. The subdivision was built in 1983. A sample of 120 houses is selected randomly and evaluated by an appraiser. If the mean appraised value of a house in this subdivision for all houses is $229,000, with a standard deviation of $8,700, what is the probability that the sample average is greater than $230,500? Appendix A Statistical Tables. (Round the values of z to 2 decimal places. Round your answer to 4 decimal places.)

Answer 1

Solution :

= / n = 8700 / 120 = 794.1977

P( > 230500) = 1 - P( < 230500)

= 1 - P[( - ) / < (230500 - 229000) / 794.1977]

= 1 - P(z < 1.89)

= 1 - 0.9706

= 0.0294

Probability = 0.0294