1.Suppose, according to a 1990 demographic report, the average U. S. household spends $90 per day.Suppose you recently took a random sample of 30 households in Huntsville and the results revealed a mean of $84.50.Suppose the standard deviation is known to be $14.50.

a.Can it be concluded that the average amount spent per day by U.S. households has decreased?(please provide 2 approached both the "T-test" and "P-value" approach.)

b.What is 95% confidence interval for the mean of daily household spent? What does this interval mean?