Question

Your friend claims that the average maximum amount of time people can hold their breath is less than 60 seconds. to check whether your friend's claim is true, you take a random sample of the maximum amount of time 10 people can hold their breath. 42 45 47 50 58 60 61 63 64 68 assume the population is approximately normal. perform a hypothesis test to determine whether the average maximum amount of time people can hold their breath is less than 60 seconds. use the alpha =0.05 level of significance.
a. state the null and alternate hypothesis
b. compute the value of the test statistic. round your intermediate calculations and final answer to at least three decimal places.
c. give the p-value
d. determine whether to reject the null hypothesis
e. state a conclusion in the context of the question (in the story of the problem)

Answer 1

Using the t-distribution, it is found that:

a)

The null hypothesis is: $H_0: \mu \geq 60$

The alternative hypothesis is: $H_1: \mu < 60$

b) t = -1.47

c) 0.0878.

d) Do not reject the null hypothesis.

e) Not enough evidence to conclude that the average maximum amount of time people can hold their breath is less than 60 seconds.

Item a:

At the null hypothesis, it is tested if the mean is not less than 60 seconds, that is:

$H_0: \mu \geq 60$

At the alternative hypothesis, it is tested if the mean is less than 60 seconds, that is:

$H_1: \mu < 60$

Item b:

We can find the standard deviation for the sample, hence, the t-distribution is used to solve this question.

The test statistic is given by:

$t = \frac{\overline{x} - \mu}{\frac{s}{\sqrt{n}}}$

The parameters are:

• $\overline{x}$ is the sample mean.

• $\mu$ is the value tested at the null hypothesis.

• s is the standard deviation of the sample.

• n is the sample size.

With the help of a calculator to find the sample mean and the standard deviation, the values of the parameters are:

$\overline{x} = 55.8, \mu = 60, s = 9.04, n = 10$

Hence, the value of the test statistic is:

$t = \frac{\overline{x} - \mu}{\frac{s}{\sqrt{n}}}$

$t = \frac{55.8 - 60}{\frac{9.04}{\sqrt{10}}}$

$t = -1.47$

Item c:

The p-value is found using a left-tailed test, as we are testing if the mean is less than a value, with 10 - 1 = 9 df and t = -1.47.

• Using a t-distribution calculator, this p-value is of 0.0878.

Item d:

The p-value is of 0.0878 > 0.05, hence, we do not reject the null hypothesis.

Item e:

Since the null hypothesis is not rejected, there is not enough evidence to conclude that the average maximum amount of time people can hold their breath is less than 60 seconds.

A similar problem is given at brainly.com/question/24826023