1. A research reposrts that the average salary of asssitant professot is $42,000. A sample of 30 associate professor has a mean salary of $43, 260. At = 0.05 test the claim that the associate professor earn more than $42,ooo per year. The standard deviation of the population is $5230.

2. A researcher claim that the average cost of mens hoes is less than $80. He selects a sample of 36pairs of shoes and foudn that the mean is 75. Using =0.01, test the claim if the standard deviation is 19.2

3. A report by the edication foundation states that the average cost of stroke victims is $24, 672. To see if the average cost is different in a hospital a researcher selec t a ransom sample of 35 victims and founda that the mean cost is $25, 226, The standard deviation is $3251. At = 0.01 can it be concluded that the average cost of victim is different from $24, 672

.4. The CEO of a large electtic utility claims that 80% of his 100,000 are very sataified with the sevice. The local newspaper surveyed 100 customers. 73% say they are satisfied. Can we reject the hypothesis that 80% of customers are satisfied. Use =0.05