Questions: A data set includes 106 body temperatures of healthy adult humans having a mean of 98.7°F and a standard deviation of 0.66°F. Construct a 99% confidence interval estimate of the mean body temperature of all healthy humans. What does the sample suggest about the use of 98.6°F as the mean body temperature?
What is the confidence interval estimate of the population mean μ ?
°F<μ< °F
(Round to three decimal places as needed.)
Transcript text: A data set includes 106 body temperatures of healthy adult humans having a mean of $98.7^{\circ} \mathrm{F}$ and a standard deviation of $0.66^{\circ} \mathrm{F}$. Construct a $99 \%$ confidence interval estimate of the mean body temperature of all healthy humans. What does the sample suggest about the use of $98.6^{\circ} \mathrm{F}$ as the mean body temperature?
What is the confidence interval estimate of the population mean $\mu$ ?
$\square$ $7^{\circ} \mathrm{F}<\mu<$ $\square$ ${ }^{\circ} \mathrm{F}$
(Round to three decimal places as needed.)
Solution
Solution Steps
Step 1: Given Data
We have a sample of body temperatures of healthy adult humans with the following statistics:
Sample mean (\(\bar{x}\)): \(98.7^{\circ} \mathrm{F}\)
Sample size (\(n\)): \(106\)
Sample standard deviation (\(s\)): \(0.66^{\circ} \mathrm{F}\)
Confidence level: \(99\%\)
Step 2: Calculate the Z-Score
For a \(99\%\) confidence level, the Z-score corresponding to the critical value is:
\[
z = 2.576
\]
Step 3: Calculate the Margin of Error
The margin of error (\(E\)) is calculated using the formula:
\[
E = z \cdot \frac{s}{\sqrt{n}} = 2.576 \cdot \frac{0.66}{\sqrt{106}} \approx 0.165
\]
Step 4: Construct the Confidence Interval
The confidence interval for the population mean (\(\mu\)) is given by:
\[
\bar{x} \pm E
\]
Calculating the lower and upper bounds:
\[
\text{Lower bound} = 98.7 - 0.165 \approx 98.535
\]
\[
\text{Upper bound} = 98.7 + 0.165 \approx 98.865
\]
Thus, the \(99\%\) confidence interval is:
\[
(98.535, 98.865)
\]
Step 5: Interpretation of the Confidence Interval
The confidence interval suggests that the true mean body temperature of all healthy humans is likely to fall within the range:
\[
98.535^{\circ} \mathrm{F} < \mu < 98.865^{\circ} \mathrm{F}
\]
Since \(98.6^{\circ} \mathrm{F}\) lies within this interval, we conclude that the sample suggests that \(98.6^{\circ} \mathrm{F}\) is a plausible mean body temperature for healthy humans.
Final Answer
The \(99\%\) confidence interval estimate of the population mean \(\mu\) is:
\[
\boxed{98.535^{\circ} \mathrm{F} < \mu < 98.865^{\circ} \mathrm{F}}
\]