High School

You wish to test the following claim [tex]\((H_a)\)[/tex] at a significance level of [tex]\(\alpha = 0.10\)[/tex].

[tex]\[
\begin{aligned}
H_o: & \quad \mu_1 = \mu_2 \\
H_a: & \quad \mu_1 > \mu_2
\end{aligned}
\][/tex]

You obtain the following two samples of data.

**Sample #1**

[tex]\[
\begin{array}{|r|r|r|r|}
\hline
67 & 52.8 & 56.2 & 48.9 \\
\hline
71 & 62.8 & 53.6 & 46.7 \\
\hline
41.1 & 47.9 & 57.5 & 49.9 \\
\hline
44.9 & 51.5 & 47.6 & 49.2 \\
\hline
55.4 & 54 & 51.1 & 53.4 \\
\hline
54.6 & 55.6 & 73.2 & 64.8 \\
\hline
62.1 & 44.5 & 63.9 & 57.3 \\
\hline
60.4 & 55.6 & 37.8 & 54.6 \\
\hline
47.3 & 41.1 & 58.9 & 41.1 \\
\hline
51.7 & 54.2 & 44 & 41.8 \\
\hline
37.8 & 71 & 54 & 65.8 \\
\hline
52.8 & 53 & 50.4 & \\
\hline
\end{array}
\][/tex]

**Sample #2**

[tex]\[
\begin{array}{|r|r|r|r|}
\hline
53.6 & 49.7 & 42.2 & 56.1 \\
\hline
37.4 & 33.9 & 56.1 & 59.9 \\
\hline
48.8 & 56.6 & 56.9 & 64.6 \\
\hline
52.9 & 61 & 50.1 & 61.8 \\
\hline
48.8 & 42.9 & 68.9 & 38.2 \\
\hline
40.5 & 63.3 & 40 & 59.5 \\
\hline
38.9 & 61 & 60.6 & 60.2 \\
\hline
33.9 & 46.4 & 64.6 & 53.6 \\
\hline
56.1 & 53.6 & 36.5 & 42.9 \\
\hline
54 & 54 & 39.5 & 38.2 \\
\hline
44.2 & 37.4 & 48.1 & 44.8 \\
\hline
48.1 & 46.2 & 71.2 & 58 \\
\hline
49.2 & 48.1 & 62.8 & 67.4 \\
\hline
52.3 & 60.2 & 68.9 & 63.9 \\
\hline
46.9 & 42.6 & 46.2 & 63.3 \\
\hline
44.2 & 50.3 & & \\
\hline
\end{array}
\][/tex]

What is the test statistic for this sample? (Report the answer accurate to three decimal places.)

Test statistic = [tex]\(\square\)[/tex]

What is the [tex]\(p\)[/tex]-value for this sample? For this calculation, use the degrees of freedom reported from the technology you are using. (Report the answer accurate to four decimal places.)

[tex]\(p\)[/tex]-value = [tex]\(\square\)[/tex]

Answer :

To solve this problem, we want to test the hypothesis that the mean from Sample #1 ([tex]\(\mu_1\)[/tex]) is greater than the mean from Sample #2 ([tex]\(\mu_2\)[/tex]). We're working with a significance level of [tex]\(\alpha = 0.10\)[/tex].

Step-by-Step Solution:

1. State the Hypotheses:
- Null Hypothesis ([tex]\(H_0\)[/tex]): [tex]\(\mu_1 = \mu_2\)[/tex]
- Alternative Hypothesis ([tex]\(H_a\)[/tex]): [tex]\(\mu_1 > \mu_2\)[/tex]

2. Set up the Data:
- Sample #1: Gather the data points provided for Sample #1.
- Sample #2: Gather the data points provided for Sample #2.

3. Calculate the Sample Statistics:
- Calculate the mean ([tex]\(\bar{x}_1\)[/tex]) and standard deviation ([tex]\(s_1\)[/tex]) for Sample #1.
- Calculate the mean ([tex]\(\bar{x}_2\)[/tex]) and standard deviation ([tex]\(s_2\)[/tex]) for Sample #2.
- Determine the sample sizes: [tex]\(n_1\)[/tex] for Sample #1 and [tex]\(n_2\)[/tex] for Sample #2.

4. Calculate the Pooled Standard Deviation:
- Use the formula for pooled standard deviation:
[tex]\[
s_p = \sqrt{\frac{(n_1 - 1)s_1^2 + (n_2 - 1)s_2^2}{n_1 + n_2 - 2}}
\][/tex]

5. Compute the Test Statistic:
- Use the formula for the two-sample t-test statistic:
[tex]\[
t = \frac{\bar{x}_1 - \bar{x}_2}{s_p \sqrt{\frac{1}{n_1} + \frac{1}{n_2}}}
\][/tex]

6. Determine Degrees of Freedom:
- The degrees of freedom for the t-distribution in this test is [tex]\(n_1 + n_2 - 2\)[/tex].

7. Find the p-value:
- Use the cumulative distribution function (CDF) for the t-distribution to find the p-value associated with the calculated test statistic. This p-value reflects the probability of observing a test statistic as extreme as, or more extreme than, the one calculated, assuming the null hypothesis is true.

8. Decision:
- Compare the p-value to the significance level [tex]\(\alpha = 0.10\)[/tex]. If the p-value is less than [tex]\(\alpha\)[/tex], reject the null hypothesis in favor of the alternative hypothesis. Otherwise, do not reject the null hypothesis.

Results:
- The test statistic calculated is approximately [tex]\(1.002\)[/tex].
- The p-value calculated is approximately [tex]\(0.1592\)[/tex].

Since the p-value ([tex]\(0.1592\)[/tex]) is greater than the significance level of [tex]\(0.10\)[/tex], we do not have enough evidence to reject the null hypothesis. Therefore, we conclude that there is not sufficient evidence to support the claim that [tex]\(\mu_1 > \mu_2\)[/tex] at the 0.10 significance level.