A Single Population Mean Using the Normal Distribution · Try It 3

shows a different random sampling of 20 cell phone models. Use these data to calculate a 93 percent confidence interval for the true mean SAR for cell phones certified for use in the United States. As previously, assume that the population standard deviation is σ = 0.337.

$$\begin{array}{cccc}\text{Phone Model}& \text{SAR}& \text{Phone Model}& \text{SAR}\\ \text{450}& \text{1.48}& \text{1450}& \text{1.53}\\ \text{550}& \text{0.8}& \text{1550}& \text{0.68}\\ \text{650}& \text{1.15}& \text{1650}& \text{1.4}\\ \text{750}& \text{1.36}& \text{1750}& \text{1.24}\\ \text{850}& \text{0.77}& \text{1850}& \text{0.57}\\ \text{950}& \text{0.462}& \text{1950}& \text{0.2}\\ \text{1050}& \text{1.36}& \text{2050}& \text{0.51}\\ \text{1150}& \text{1.39}& \text{2150}& \text{0.3}\\ \text{1250}& \text{1.3}& \text{2250}& \text{0.73}\\ \text{1350}& \text{0.7}& \text{2350}& \text{0.869}\end{array}$$

OpenStax, Statistics · §8.1 A Single Population Mean Using the Normal Distribution · Try It 3