Answer :
To tackle this hypothesis testing problem, let's go through the steps to find the test statistic and p-value:
### Step-by-Step Solution:
#### a) Calculating the Test Statistic
1. Identify the Given Information:
- Sample sizes: [tex]\( n_1 = 18 \)[/tex], [tex]\( n_2 = 19 \)[/tex]
- Sample means: [tex]\( \bar{x}_1 = 53.4 \)[/tex], [tex]\( \bar{x}_2 = 59.1 \)[/tex]
- Sample standard deviations: [tex]\( s_1 = 12.2 \)[/tex], [tex]\( s_2 = 10.9 \)[/tex]
2. Calculate the Pooled Standard Deviation (Sp):
Since we have equal variances assumption, the pooled standard deviation formula is used:
[tex]\[
S_p = \sqrt{\frac{(n_1 - 1)s_1^2 + (n_2 - 1)s_2^2}{n_1 + n_2 - 2}}
\][/tex]
Substituting in the values:
[tex]\[
S_p = \sqrt{\frac{(18 - 1) \times (12.2)^2 + (19 - 1) \times (10.9)^2}{18 + 19 - 2}}
\][/tex]
[tex]\[
S_p = \sqrt{\frac{17 \times 148.84 + 18 \times 118.81}{35}}
\][/tex]
[tex]\[
S_p = \sqrt{\frac{2521.28 + 2138.58}{35}}
\][/tex]
[tex]\[
S_p = \sqrt{\frac{4659.86}{35}}
\][/tex]
[tex]\[
S_p \approx 11.51
\][/tex]
3. Calculate the Standard Error (SE) for the Difference in Means:
[tex]\[
SE = S_p \times \sqrt{\frac{1}{n_1} + \frac{1}{n_2}}
\][/tex]
[tex]\[
SE = 11.51 \times \sqrt{\frac{1}{18} + \frac{1}{19}}
\][/tex]
[tex]\[
SE \approx 11.51 \times \sqrt{0.0556 + 0.0526}
\][/tex]
[tex]\[
SE \approx 11.51 \times \sqrt{0.1082}
\][/tex]
[tex]\[
SE \approx 11.51 \times 0.329
\][/tex]
[tex]\[
SE \approx 3.79
\][/tex]
4. Compute the Test Statistic (t):
[tex]\[
t = \frac{\bar{x}_1 - \bar{x}_2}{SE}
\][/tex]
[tex]\[
t = \frac{53.4 - 59.1}{3.79}
\][/tex]
[tex]\[
t \approx \frac{-5.7}{3.79}
\][/tex]
[tex]\[
t \approx -1.50
\][/tex]
Therefore, the test statistic is approximately [tex]\(-1.50\)[/tex].
#### b) Calculating the p-value
1. Calculate the degrees of freedom (df):
[tex]\[
df = n_1 + n_2 - 2 = 18 + 19 - 2 = 35
\][/tex]
2. Find the p-value for the one-tailed t-test:
Using a t-distribution table or software with [tex]\( df = 35 \)[/tex] and the calculated test statistic [tex]\( t = -1.50 \)[/tex], we determine the p-value.
The p-value is approximately [tex]\( 0.0712 \)[/tex].
### Conclusion:
- Test Statistic: [tex]\(-1.50\)[/tex]
- p-value: [tex]\(0.0712\)[/tex]
Since the p-value [tex]\(0.0712\)[/tex] is greater than the significance level [tex]\(\alpha = 0.001\)[/tex], we do not reject the null hypothesis [tex]\(H_0\)[/tex]. There isn't enough evidence to support the claim that [tex]\(\mu_1 < \mu_2\)[/tex] at the [tex]\(0.001\)[/tex] significance level.
### Step-by-Step Solution:
#### a) Calculating the Test Statistic
1. Identify the Given Information:
- Sample sizes: [tex]\( n_1 = 18 \)[/tex], [tex]\( n_2 = 19 \)[/tex]
- Sample means: [tex]\( \bar{x}_1 = 53.4 \)[/tex], [tex]\( \bar{x}_2 = 59.1 \)[/tex]
- Sample standard deviations: [tex]\( s_1 = 12.2 \)[/tex], [tex]\( s_2 = 10.9 \)[/tex]
2. Calculate the Pooled Standard Deviation (Sp):
Since we have equal variances assumption, the pooled standard deviation formula is used:
[tex]\[
S_p = \sqrt{\frac{(n_1 - 1)s_1^2 + (n_2 - 1)s_2^2}{n_1 + n_2 - 2}}
\][/tex]
Substituting in the values:
[tex]\[
S_p = \sqrt{\frac{(18 - 1) \times (12.2)^2 + (19 - 1) \times (10.9)^2}{18 + 19 - 2}}
\][/tex]
[tex]\[
S_p = \sqrt{\frac{17 \times 148.84 + 18 \times 118.81}{35}}
\][/tex]
[tex]\[
S_p = \sqrt{\frac{2521.28 + 2138.58}{35}}
\][/tex]
[tex]\[
S_p = \sqrt{\frac{4659.86}{35}}
\][/tex]
[tex]\[
S_p \approx 11.51
\][/tex]
3. Calculate the Standard Error (SE) for the Difference in Means:
[tex]\[
SE = S_p \times \sqrt{\frac{1}{n_1} + \frac{1}{n_2}}
\][/tex]
[tex]\[
SE = 11.51 \times \sqrt{\frac{1}{18} + \frac{1}{19}}
\][/tex]
[tex]\[
SE \approx 11.51 \times \sqrt{0.0556 + 0.0526}
\][/tex]
[tex]\[
SE \approx 11.51 \times \sqrt{0.1082}
\][/tex]
[tex]\[
SE \approx 11.51 \times 0.329
\][/tex]
[tex]\[
SE \approx 3.79
\][/tex]
4. Compute the Test Statistic (t):
[tex]\[
t = \frac{\bar{x}_1 - \bar{x}_2}{SE}
\][/tex]
[tex]\[
t = \frac{53.4 - 59.1}{3.79}
\][/tex]
[tex]\[
t \approx \frac{-5.7}{3.79}
\][/tex]
[tex]\[
t \approx -1.50
\][/tex]
Therefore, the test statistic is approximately [tex]\(-1.50\)[/tex].
#### b) Calculating the p-value
1. Calculate the degrees of freedom (df):
[tex]\[
df = n_1 + n_2 - 2 = 18 + 19 - 2 = 35
\][/tex]
2. Find the p-value for the one-tailed t-test:
Using a t-distribution table or software with [tex]\( df = 35 \)[/tex] and the calculated test statistic [tex]\( t = -1.50 \)[/tex], we determine the p-value.
The p-value is approximately [tex]\( 0.0712 \)[/tex].
### Conclusion:
- Test Statistic: [tex]\(-1.50\)[/tex]
- p-value: [tex]\(0.0712\)[/tex]
Since the p-value [tex]\(0.0712\)[/tex] is greater than the significance level [tex]\(\alpha = 0.001\)[/tex], we do not reject the null hypothesis [tex]\(H_0\)[/tex]. There isn't enough evidence to support the claim that [tex]\(\mu_1 < \mu_2\)[/tex] at the [tex]\(0.001\)[/tex] significance level.