Question

In Exercises 9–12, refer to the exercise identified. Make subjective estimates to decide whether results are significantly low or significantly high, then state a conclusion about the original claim. For example, if the claim is that a coin favours heads and sample results consist of 11 heads in 20 flips, conclude that there is not sufficient evidence to support the claim that the coin favours heads (because it is easy to get 11 heads in 20 flips by chance with a fair coin).

Exercise 8 “Pulse Rates”

Short answer

The result of 11.3 bpm isneither significantly low nor significantly high.

There is enough evidence to reject the claim that the standard deviation of pulse rates of adult males is more than 11 bpm.

Step-by-step solution

Given information

Refer to Exercise 8 BSC; for a sample of 153 adult males, the mean pulse rate is equal to 69.6 bpm, and the standard deviation is equal to 11.3 bpm.

Conclusion

It is claimed that the standard deviation of the pulse rate of adult males is more than 11 bpm.

That is, $\sigma >11\text{bpm}$

Since the value of 11.3 bpm is not considerably greater than the claimed value of 11 bpm, it appears to be likely to obtain a standard deviation of 11.3 bpm in a sample when the true standard deviation of pulse rates is 11 bpm.

Therefore, the result of 11.3 bpm is neither significantly low nor significantly high.

Thus, this suggests that there is enough evidence to reject the claim that the standard deviation of pulse rates of adult males is more than 11 bpm.