Two treatments for a new infectious disease have been developed to reduce hospitalizations. Each treatment was given to different groups of patients. Treatment 1 was given to 65 people. Subjects of treatment 1 had a mean hospital stay of 5.6 days with a standard deviation of 2.6 days. Treatment 2 was given to 54 people. Subjects of treatment 2 had a mean hospital stay of 8.4 days with a standard deviation of 3.0 days. Use the method of hypothesis testing to test the claim that the mean time in the hospital for treatment 1 is shorter than the mean time in the hospital for treatment 2 assuming a 0.05 significance level. (a) List the null and alternative hypotheses for this test. (b) Compute the value of the test statistic (c) Determine the rejection region.

Definition Definition Measure of central tendency that is the average of a given data set. The mean value is evaluated as the quotient of the sum of all observations by the sample size. The mean, in contrast to a median, is affected by extreme values. Very large or very small values can distract the mean from the center of the data. Arithmetic mean: The most common type of mean is the arithmetic mean. It is evaluated using the formula: μ = 1 N ∑ i = 1 N x i Other types of means are the geometric mean, logarithmic mean, and harmonic mean. Geometric mean: The nth root of the product of n observations from a data set is defined as the geometric mean of the set: G = x 1 x 2 ... x n n Logarithmic mean: The difference of the natural logarithms of the two numbers, divided by the difference between the numbers is the logarithmic mean of the two numbers. The logarithmic mean is used particularly in heat transfer and mass transfer. ln x 2 − ln x 1 x 2 − x 1 Harmonic mean: The inverse of the arithmetic mean of the inverses of all the numbers in a data set is the harmonic mean of the data. 1 1 x 1 + 1 x 2 + ...