4. A tool industry publication claims that the average salary for executives is $129,500 and the standard deviation of all salaries in the industry is $13,500, a study of 20 executives finds that the average salary is $136, 700 with a standard deviation of $22,570.
(5) Identify: = _________, s = __________, ? = _________, Ï? = _________, n = __________
a) (2) What is the probability that a single-family home in that region used more than 1075 kW?
c) (4) For the sample of 50 different, randomly selected homes, find the probability that their mean energy consumption level for September was greater than 1075 kW?
d) (4) Compare the results for part A and part C, and explain why the probabilities changed
The solution provides step by step method for the calculation of probability using the Z score. Formula for the calculation and Interpretations of the results are also included.