O CONFIDENCE INTERVALS AND HYPOTHESIS TESTING Kin Confidence interval for the difference of population means: Use.. V For a study conducted by the research department of a pharmaceutical company, 280 randomly selected individuals were asked to report the amount of money they spend annually on prescription allergy relief medication. The sample mean was found to be $ 17.70 with a standard deviation of $5.10 . A random sample of 285 individuals was selected independently of the first sample. These individuals reported their annual spending on non-prescription allergy relief medication The mean of the second sample was found to be $18.30 with a standard deviation of $4.40 . As the sample sizes were quite large, it was assumed that the respective population standard deviations of the spending for prescription and non-prescription allergy relief medication could be estimated as the respective sample standard deviation values given above. Construct a 95 % confidence interval for the difference , - u, between the mean spending on prescription allergy relief medication (M) and the mean spending on non-prescription allergy relief medication (U,). Then find the lower limit and upper limit of the 95% confidence interval. Carry your intermediate computations to at least three decimal places. Round your answers to at least two decimal places. (If necessary, consult a list of formulas.) Lower limit: X 5 ? Upper limit