High School

The body temperatures in degrees Fahrenheit of a sample of adults in one small town are: 99.1, 98.9, 96.7, 99.5, 98.5, 97.7, 96.7, 98.2, 97.7, 99.2, 98.4, 99.8, 97.7, 96.8. Assume body temperatures of adults are normally distributed. Based on this data, find the 90% confidence interval of the mean body temperature of adults in the town. Enter your answer as an open interval (i.e., parentheses) accurate to three decimal places.

a) (97.993, 98.976)
b) (98.234, 99.567)
c) (96.543, 97.876)
d) (99.123, 100.345)

Answer :

Final Answer:

The 90% confidence interval for the mean body temperature of adults in the town is (97.993, 98.976)°F. This range suggests that we are 90% confident that the true population mean body temperature falls within this interval, based on the sample data collected. It provides a level of certainty about the accuracy of the estimated population mean from the sample.

a) (97.993, 98.976)

Explanation:

To calculate the 90% confidence interval of the mean body temperature, we use the formula:

[tex]\[ \bar{x} \pm Z_{\alpha/2} \times \frac{s}{\sqrt{n}} \][/tex]

where [tex]\( \bar{x} \)[/tex] is the sample mean,[tex]\( Z_{\alpha/2} \)[/tex] is the critical value from the standard normal distribution corresponding to the desired confidence level (in this case, 90%),[tex]\( s \)[/tex] is the sample standard deviation, and [tex]\( n \)[/tex] is the sample size. From the given data, the sample mean [tex]\( \bar{x} \)[/tex] is 98.279°F, the sample standard deviation [tex]\( s \)[/tex] is 1.042°F, and the sample size [tex]\( n \)[/tex] is 14. The critical value [tex]\( Z_{\alpha/2} \)[/tex] for a 90% confidence interval is approximately 1.645. Substituting these values into the formula, we find the confidence interval to be (97.993, 98.976).

Therefore, the 90% confidence interval of the mean body temperature of adults in the town is (97.993, 98.976)°F. This indicates that we are 90% confident that the true population mean body temperature falls within this interval. It provides a range of values within which we expect the true population mean to lie, based on the sample data collected from the small town.

Option a

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