Matched or Paired Samples (Optional) · Try It 1

A study was conducted to investigate how effective a new diet was in lowering cholesterol. Results for the randomly selected subjects are shown in the table. The differences have a normal distribution. Are the subjects’ cholesterol levels lower on average after the diet? Test at the 5 percent level.

$$\begin{array}{cccccccccc}\text{Subject}& \text{A}& \text{B}& \text{C}& \text{D}& \text{E}& \text{F}& \text{G}& \text{H}& \text{I}\\ \text{Before}& \text{209}& \text{210}& \text{205}& \text{198}& \text{216}& \text{217}& \text{238}& \text{240}& \text{222}\\ \text{After}& \text{199}& \text{207}& \text{189}& \text{209}& \text{217}& \text{202}& \text{211}& \text{223}& \text{201}\end{array}$$

OpenStax, Statistics · §10.4 Matched or Paired Samples (Optional) · Try It 1