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The dean of a university estimates that the mean number of classroom hours per week for full-time faculty is 10.0. As a member of the student council, you want to test this claim. A random sample of the number of classroom hours for eight full-time faculty for one week is shown in the table below. At [tex]\alpha = 0.05[/tex], can you reject the dean's claim? Complete parts (a) through (d) below. Assume the population is normally distributed.

| 10.7 | 8.2 | 11.4 | 7.5 | 4.4 | 11.2 | 12.2 | 9.0 |

(a) Write the claim mathematically and identify [tex]H_0[/tex] and [tex]H_a[/tex].

Which of the following correctly states [tex]H_0[/tex] and [tex]H_a[/tex]?

A. [tex]H_0: \mu = 10.0[/tex] and [tex]H_a: \mu \neq 10.0[/tex]

B. [tex]H_0: \mu \leq 10.0[/tex] and [tex]H_a: \mu \ \textgreater \ 10.0[/tex]

C. [tex]H_0: \mu \geq 10.0[/tex] and [tex]H_a: \mu \ \textless \ 10.0[/tex]

D. [tex]H_0: \mu \ \textless \ 10.0[/tex] and [tex]H_a: \mu \geq 10.0[/tex]

E. [tex]H_0: \mu \neq 10.0[/tex] and [tex]H_a: \mu = 10.0[/tex]

F. [tex]H_0: \mu \ \textgreater \ 10.0[/tex] and [tex]H_a: \mu \leq 10.0[/tex]

(b) Use technology to find the P-value.
[tex]P = \square[/tex] (Round to three decimal places as needed.)


Sagot :

Sure, let's work through the problem step-by-step.

### (a) Write the claim mathematically and identify [tex]\( H_0 \)[/tex] and [tex]\( H_a \)[/tex]

The claim made by the dean is that the mean number of classroom hours per week for full-time faculty is [tex]\(10.0\)[/tex]. This can be written mathematically as:

[tex]\[ \mu = 10.0 \][/tex]

When testing this claim, we set up the null hypothesis [tex]\(H_0\)[/tex] and the alternative hypothesis [tex]\(H_a\)[/tex].

- The null hypothesis [tex]\(H_0\)[/tex] represents the claim made by the dean:
[tex]\[ H_0: \mu = 10.0 \][/tex]

- The alternative hypothesis [tex]\(H_a\)[/tex] represents what we want to test against the null hypothesis. In this case, since we want to test if the mean is different from [tex]\(10.0\)[/tex] (either greater than or less than), we use a two-tailed test:
[tex]\[ H_a: \mu \neq 10.0 \][/tex]

So, the correct statements for [tex]\(H_0\)[/tex] and [tex]\(H_a\)[/tex] are:

[tex]\[ \boxed{H_0: \mu = 10.0, \quad H_a: \mu \neq 10.0} \][/tex]

This corresponds to option E.

### (b) Use technology to find the P-value

Given the sample data for the number of classroom hours:

[tex]\[ 10.7, 8.2, 11.4, 7.5, 4.4, 11.2, 12.2, 9.0 \][/tex]

We can summarize the results of our calculations as follows:

- The sample mean ([tex]\(\bar{x}\)[/tex]) is:
[tex]\[ 9.325 \][/tex]

- The sample standard deviation ([tex]\(s\)[/tex]) is:
[tex]\[ 2.589 \][/tex]

- The t-statistic (t) is calculated using the formula:
[tex]\[ t = \frac{\bar{x} - \mu}{s/\sqrt{n}} \][/tex]

Substituting the values:
[tex]\[ t = \frac{9.325 - 10.0}{2.589 / \sqrt{8}} \approx -0.737 \][/tex]

- Degrees of freedom ([tex]\(df\)[/tex]):
[tex]\[ df = n - 1 = 8 - 1 = 7 \][/tex]

- Using a two-tailed test, the P-value is:
[tex]\[ P = 0.485 \][/tex]

### Conclusion:
Given the significance level [tex]\(\alpha = 0.05\)[/tex]:

Since the P-value [tex]\((0.485)\)[/tex] is greater than [tex]\(\alpha (0.05)\)[/tex], we fail to reject the null hypothesis [tex]\(H_0\)[/tex]. This means there is not enough evidence to reject the dean's claim that the mean number of classroom hours per week for full-time faculty is [tex]\(10.0\)[/tex].

Thus, the final solution is:

[tex]\[ H_0: \mu = 10.0 \][/tex]
[tex]\[ H_a: \mu \neq 10.0 \][/tex]
[tex]\[ \text{P-value} = 0.485 \][/tex]

Since [tex]\( \text{P-value} > 0.05 \)[/tex], we do not reject [tex]\( H_0 \)[/tex].
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