91影视

The summary of the results for the pulse rates of women is given.

The sample standard deviation for 147 sampled women is 12.5 bpm.

The normal range of pulse rates is 60 to 100 beats per minute, used to estimate the standard deviation.

Using the normal range, the estimate for the standard deviation of pulse rates is obtained as follows.

$$\begin{gathered} {蟽}_0=\frac{Range}{4} \\ =\frac{100-60}{4} \\ =10 \end{gathered}$$

To test the significance of theclaim that the pulse rates of women have a standard deviation equal to 10 beats per minute, the null and alternative hypothesis is formulated as follows.

$$\begin{gathered} H_0:蟽=10 \\ {H}_1:蟽鈮�10 \end{gathered}$$

Here, $蟽$is the actual standard deviation of all women.

The test statistic is obtained from the output as 229.7176 $\left({蠂}^2\right)$with the degree of freedom (DF) as 146. The chi-square test is a right-tailed test, and the p-value for the test is 0.0001.

For the given level of significance, if the p-value is lesser than 0.05, the null hypothesis will be rejected. Otherwise, fail to reject the null hypothesis.

In this case, the p-value is lesser than 0.05. So, reject the null hypothesis.

As the null hypothesis is rejected, it can be concluded that there is not enough evidence to support the claim that the pulse rates of women have a standard deviation of 10 bpm.

It indicates that the effectiveness of using the range rule of thumb with a normal range of 60 to 100 beats per minute is not a good standard deviation for estimating $蟽$, as it does not support the sampled results.