Chapter 8, Problem 119P

study was recently reported comparing the effects of different dietary patterns on blood pressure within an 8-week follow-up period [16]. Subjects were randomized to three groups: A, a control diet group, N = 154; B, a fruits-andvegetables diet group, N = 154; C, a combination-diet group consisting of a diet rich in fruits, vegetables, and lowfat dairy products and with reduced saturated and total fat, N = 151. The results reported for systolic blood pressure (SBP) are shown in Table 8.29.

Table 8.29 Effects of dietary pattern on change in SBP

Suppose we want to compute a two-sided 95% CI for the true mean change in the fruits-and-vegetables group minus the true mean change in the control group, which we represent by (c1, c2). Without doing any further calculations, which of the following statement(s) must be false?

(1) The lower confidence limit (c₁) = −5.0.

(2) The upper confidence limit (c₂) = −1.0.

(3) The width of the CI (c₂ − c₁) = 3.0.

[Note: The actual values of c₁, c₂, or (c₂ − c₁) may differ from given above.]