3 Utility Bill In your town a sample of 64 residents had an

3. Utility Bill... In your town, a sample of 64 residents had an average utility bill of $185 month. The standard deviation of the population is $16.50. Suppose you have decided to help out 500 residents by paying all their utility bills. At the 90% confidence level, what is the maximum total that you would expect to pay?

4. Assistant coaches salary. An athletic director claims that the average salary of assistant coaches at 4-year colleges in Texas is $72,000. A sample of 100 assistant coaches from Texas has a mean salary of $73,260. The standard deviation of the population of all assistant coaches’ salaries is $8530. If you were to test this claim, what would be the p-value (4-place decimal accuracy)?

Solution

Q4.

Set Up Hypothesis
Null Hypothesis H0: U=72000
Alternate Hypothesis H1: U!=72000
Test Statistic
Population Mean(U)=72000
Given That X(Mean)=73260
Standard Deviation(S.D)=8530
Number (n)=100
we use Test Statistic (Z) = x-U/(s.d/Sqrt(n))
Zo=73260-72000/(8530/Sqrt(100)
Zo =1.4771
| Zo | =1.4771
P-Value : Two Tailed ( double the one tail ) - Ha : ( P != 1.4771 ) = 0.1396