A one-sided confidence interval can be used if the information you are predicting is known to come from an interval with no limit on one side or when we are only interested in an upper bound for a parameter. For the case of n = 400 and = 39 and X = 544 construct one-sided intervals of the form (, a) for the population mean at 80%, 90%, 95% and 99% confidence.

(I finish this question, but not sure this is correct or not, please help me to check this.)

80% (-,546.52)

90% (-,547.22)

95%. (-,547.82)

98%. (-, 548.54)