A construction company figures the cost of a project based on an average idle time of 68 minutes (per worker per 8 hour period). The std. dev is 10 minutes. A new work schedule has just been completed by the foreman. It is not known whether this schedule will change idle time or not. To determine if there is a change, a random sample of 49 workers was observed during an 8 hour shift. The average idle time was 65 minutes. Use a 5% significance level to determine if there is a change in idle time.
a. Find the critical values for z from the table
b. Find the z test statistic
c. Find the p-value for this test
d. Would you reject the null hypothesis at the 5% significance level?
e. If alpha were changed to 1%, would you reject the null hypothesis?