EXAMPLE 16 intervals for using technology

cerealsodium

For the breakfast cereal data in Example 14, construct a 99% confidence interval for the population mean sodium content, using the TI-83/84, Minitab, and SPSS.

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Solution

We use the instructions provided in the Step-by-Step Technology Guide below. The sample size is not large (≤30), so it is necessary to check for normality. Figure 17 indicates acceptable normality.

The results for the TI-83/84 in Figure 19 display the 95% confidence interval for the population mean sodium content to be

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Figure 8.19: FIGURE 19 TI-83/84 results.

They also show the sample mean , the sample standard deviation , and the sample size .

The Minitab results are shown in Figure 20, providing the sample size , the sample mean , the sample standard deviation , the standard error (SE mean) 14.2, and the 95% confidence interval (155.7, 216.2).

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Figure 8.20: FIGURE 20 Minitab results.

The SPSS results are shown in Figure 21, providing the sample mean , the standard error 14.20254, and the 95% confidence interval (155.6655, 216.2095).

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Figure 8.21: FIGURE 21 SPSS results.