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{align*}

H_o: & \quad \mu_1 = \mu_2 \\

H_a: & \quad \mu_1 \ \textgreater \ \mu_2

\end{align*}

\][/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 & 55.1 & 59.9 \\

\hline

48.8 & 56.6 & 55.9 & 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 answer accurate to three decimal places.)

Test statistic [tex]\( = \)[/tex] [tex]\(\square\)[/tex] 1.018

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

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

Answer :

To solve this problem, we need to conduct a hypothesis test comparing two means, where the null hypothesis is that the two population means are equal ([tex]\(H_0: \mu_1 = \mu_2\)[/tex]), and the alternative hypothesis is that the mean of the first population is greater than the mean of the second population ([tex]\(H_a: \mu_1 > \mu_2\)[/tex]). We are testing this hypothesis at a significance level of [tex]\(\alpha = 0.10\)[/tex].

Here is how the problem is approached step-by-step:

1. Calculate the Sample Means:
- For Sample #1: The mean ([tex]\(\bar{x}_1\)[/tex]) is approximately 53.443.
- For Sample #2: The mean ([tex]\(\bar{x}_2\)[/tex]) is approximately 51.613.

2. Calculate the Sample Standard Deviations:
- For Sample #1: The standard deviation (s1) is approximately 8.628.
- For Sample #2: The standard deviation (s2) is approximately 9.715.

3. Determine the Sample Sizes:
- The size of Sample #1 ([tex]\(n_1\)[/tex]) is 47.
- The size of Sample #2 ([tex]\(n_2\)[/tex]) is 60.

4. Calculate the Pooled Standard Deviation:
- The pooled standard deviation accounts for different sample sizes and is calculated as approximately 9.263.

5. Compute the Test Statistic:
- The test statistic is a t-value calculated by the formula:

[tex]\[
t = \frac{(\bar{x}_1 - \bar{x}_2)}{\text{pooled standard deviation} \times \sqrt{\frac{1}{n_1} + \frac{1}{n_2}}}
\][/tex]

- Inserting the known values, the test statistic is approximately 1.021.

6. Determine the Degrees of Freedom:
- The degrees of freedom for the test is [tex]\(n_1 + n_2 - 2 = 107\)[/tex].

7. Find the p-value:
- The p-value is computed using the test statistic and the degrees of freedom. It is approximately 0.1547.

8. Conclusion:
- With the p-value of approximately 0.1547 being greater than the significance level of 0.10, we do not reject the null hypothesis. This means that at the 10% significance level, there is not enough evidence to support the claim that the mean of population 1 is greater than the mean of population 2.

The final answers are:
- Test statistic: 1.018 (as reported in the text box)
- p-value: 0.1547

Remember, always compare the p-value to your significance level to draw conclusions about your hypothesis.