Consider the following hypothesis test: h0: 20 ha: < 20 a sample of 55 provided a sample mean of 19.5. the population standard deviation is 1.8. a. compute the value of the test statistic (to 2 decimals). b. what is the p-value (to 3 decimals)? c. using = .05, can it be concluded that the population mean is less than 20? d. using = .05, what is the critical value for the test statistic? e. state the rejection rule: reject h0 if z is the critical value. f. using = .05, can it be concluded that the population mean is less than