High School

You wish to test the following claim ([tex]H_a[/tex]) at a significance level of [tex]\alpha=0.005[/tex].

[tex]
\begin{align*}
H_0: & \quad \mu_1 = \mu_2 \\
H_a: & \quad \mu_1 \neq \mu_2
\end{align*}
[/tex]

You obtain the following two samples of data.

**Sample #1**

[tex]
\begin{array}{|r|r|r|r|}
\hline
104.3 & 73.8 & 71.4 & 77.7 \\
\hline
92 & 87.4 & 90 & 89.2 \\
\hline
81.9 & 75.8 & 85 & 63.4 \\
\hline
90.4 & 111 & 79.5 & 100.6 \\
\hline
96.2 & 79.9 & 86.7 & 69.9 \\
\hline
97.9 & 97.9 & 86.7 & 77.4 \\
\hline
75 & 77.4 & 87.4 & 95.7 \\
\hline
86.4 & 86 & 105.5 & 84.3 \\
\hline
99.9 & 95.2 & 68.7 & 91.6 \\
\hline
69.9 & 65.2 & 88.1 & 102.3 \\
\hline
90.8 & & & \\
\hline
\end{array}
[/tex]

**Sample #2**

[tex]
\begin{array}{|r|r|r|r|}
\hline
92.8 & 59.6 & 90.1 & 82.6 \\
\hline
82.6 & 86.4 & 69.2 & 94.6 \\
\hline
73.3 & 74.8 & 68.1 & 69.7 \\
\hline
81.9 & 65.9 & 81.5 & 92.8 \\
\hline
89.8 & 96.1 & 90.9 & 68.1 \\
\hline
78.2 & 84.3 & 102.4 & 78.2 \\
\hline
75.6 & 79.4 & 77.7 & 73.3 \\
\hline
88.7 & 84.1 & 82.4 & 87.2 \\
\hline
88.7 & 88.1 & 82.4 & 85.6 \\
\hline
94.6 & 59.6 & 80.1 & 81 \\
\hline
86.6 & 75.4 & 83.1 & 68.7 \\
\hline
\end{array}
[/tex]

1. What is the test statistic for this sample? (Report answer accurate to three decimal places.)
- Test statistic [tex]= \square[/tex]

2. 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.)
- [tex]p[/tex]-value [tex]= \square[/tex]

Answer :

To solve this problem, we need to perform a two-sample t-test to compare the means of two independent samples. Here is a step-by-step approach:

### Step 1: Understand the Hypotheses
- Null Hypothesis ([tex]\(H_0\)[/tex]): [tex]\(\mu_1 = \mu_2\)[/tex], meaning the means of the two samples are equal.
- Alternative Hypothesis ([tex]\(H_a\)[/tex]): [tex]\(\mu_1 \neq \mu_2\)[/tex], meaning the means of the two samples are not equal.

### Step 2: Gather the Data
- Sample 1 consists of the following values:
[tex]\[
[104.3, 73.8, 71.4, 77.7, \ldots , 90.8] \quad \text{(41 values total)}
\][/tex]

- Sample 2 consists of the following values:
[tex]\[
[92.8, 59.6, 90.1, 82.6, \ldots , 68.7] \quad \text{(44 values total)}
\][/tex]

### Step 3: Perform the Two-Sample t-Test
The two-sample t-test compares the means of the two samples assuming they come from populations with equal variances and the samples are independent and normally distributed.

### Step 4: Calculate the Test Statistic
The test statistic reflects the difference between the sample means relative to the variability of the samples.

### Step 5: Determine the p-value
The p-value indicates the probability of observing the test statistic or something more extreme if the null hypothesis is true.

### Results
- Test Statistic: [tex]\(2.139\)[/tex]
- p-value: [tex]\(0.0354\)[/tex]

### Step 6: Decision
- Compare the p-value to the significance level [tex]\(\alpha = 0.005\)[/tex].
- Since [tex]\(0.0354 > 0.005\)[/tex], we fail to reject the null hypothesis.

### Conclusion
There is not enough statistical evidence at the [tex]\(0.005\)[/tex] significance level to conclude that there is a difference in the means of the two samples. The data does not show a significant difference between the group means.