1. Suppose that you were interested in finding if noise has any effect on blood pressure. You randomly assigned 22 individuals to either a control or an experimental group (HI = 112). Subjects in the quiet group {I} relaxed in comfortable chairs in a quiet room for 30 minutes. At the end of the 30 minutes you measured their systolic blood pressure (Le, the blood pressure during the contraction of the heart). Subjects in the noise group (2) also sat in the chairs for 30 minutes. During the it-minute wait, how- ever, they listened to a recording of rush hour traffic noise from a large city. After lis- tening to the noise for 30 minutes, the systolic blood pressure of these subjects was also recorded. Suppose that you obtained the following blood pressures in millimeters of mercury. Quiet (X1) Noise {X2} 106 141 1]? 136 124 124 129 139 115 121 131 119 12] 14? 115 128 128 115 136 134 12? 14H 3. What type of research design, between-subjects or within-subjects, was used in this study? I}. Find the mean and standard deviation for each group. Then use a t test to answer the following question: Does noise affect systolic blood pressure? Use a two-tailed test and a .115 significance level. 0. What is the value of 112 for this experiment? What proportion of the variance in the dependent variable can be accounted for by knowing the level of the independent variable? d. Find the 95 percent confidence interval for the difference between the two popula- tion means. e. Describe your results following the example illustrated in the Reporting the Results of a {Test section of this chapter