In a randomized, double-blind experiment, 150 babies were randomly divided into a treatment group (n1 = 75) and a control group (n2 = 75) . After the study, the treatment group had a mean serum retinol concentration of 43.66 micrograms per deciliter (pg/dL) with a standard deviation of 16.89 pg/dL, while the control group had a mean serum retinol concentration of 14.94 pg/dL with a standard deviation of 11.41 pg/dL. Does the treatment group have a higher standard deviation for serum retinol concentration than the control group at the or: 0.01 level of signicance? It is known that serum retinol concentration is normally distributed. Use the P-value approach to perform the test. Let 61 represent the population standard deviation for the treatment group and 62 represent the population standard deviation for the control group. State the null and alternative hypotheses for this test. Use technology to nd the P-value for this test. The P-value is (Round to three decimal places as needed.) A certain company's executives want to experiment with redesigning its restaurants so that the customers form one line leading to four registers to place orders, rather than four lines leading to four separate registers. They redesign 20 randomly selected restaurants with the single line. In addition, they randomly select 20 restaurants with the four-line conguration to participate in the study. At each restaurant, an employee monitors the wait time (in minutes) of randomly selected patrons. The data are shown in the accompanying table. Note that normal probability plots indicate that the data are normally distributed. Complete parts (a) and (b). a Click the icon to view the data table. (a) Is the variability in wait time in the single line less than that for the multiple lines at the ot= 0.05 level of signicance? Use the P-value approach to perform the test. Let (:1 represent the population standard deviation for the wait time in the single line and 0'2 represent the population standard deviation for the wait time in the multiple lines. State the null and alternative hypotheses for this test. H0: 01 =