a test of sobriety involves measuring the subject's motor skills. twenty randomly selected sober subjects take the test and produce a mean score of 41.0 with a standard deviation of 3.7. at the 0.01 level of significance, test the claim that the true mean score for all sober subjects is equal to 35.0. use the traditional method of testing hypotheses.

Respuesta :

Answer:

Since the pvalue of the test is 0 < 0.01, we reject the null hypothesis and accept the alternate hypothesis that the true mean score for all sober subjects is different of 35.

Step-by-step explanation:

Test the claim that the true mean score for all sober subjects is equal to 35.0.

This means that the null hypothesis is:

[tex]H_{0}: \mu = 35[/tex]

And the alternate hypothesis is:

[tex]H_{a}: \mu \neq 35[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

35 is tested at the null hypothesis:

This means that [tex]\mu = 35[/tex]

Sample of 20, mean score of 41.0 with a standard deviation of 3.7.

This means that [tex]n = 20, X = 41, \sigma = 3.7[/tex]

Value of test statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{41 - 35}{\frac{3.7}{\sqrt{20}}}[/tex]

[tex]z = 7.25[/tex]

Pvalue of the test:

The pvalue of the test is the probability that differs from the mean by at least 41 - 35 = 6, which is the probability that |z| < 7.25.

z = -7.25 has a pvalue of 0

2*0 = 0

Since the pvalue of the test is 0 < 0.01, we reject the null hypothesis and accept the alternate hypothesis that the true mean score for all sober subjects is different of 35.