Using the t-distribution, as we have the standard deviation for the sample, it is found that there is a significant difference between the wait times for the two populations.
<h3>What are the hypothesis tested?</h3>
At the null hypothesis, we test if there is no difference, that is:
![H_0: \mu_A - \mu_B = 0](https://tex.z-dn.net/?f=H_0%3A%20%5Cmu_A%20-%20%5Cmu_B%20%3D%200)
At the alternative hypothesis, it is tested if there is difference, that is:
![H_1: \mu_A - \mu_B = 0](https://tex.z-dn.net/?f=H_1%3A%20%5Cmu_A%20-%20%5Cmu_B%20%3D%200)
<h3>What are the mean and the standard error of the distribution of differences?</h3>
For each sample, we have that:
![\mu_A = 73, s_A = \frac{2}{\sqrt{100}} = 0.2](https://tex.z-dn.net/?f=%5Cmu_A%20%3D%2073%2C%20s_A%20%3D%20%5Cfrac%7B2%7D%7B%5Csqrt%7B100%7D%7D%20%3D%200.2)
![\mu_B = 74, s_B = \frac{4}{\sqrt{100}} = 0.4](https://tex.z-dn.net/?f=%5Cmu_B%20%3D%2074%2C%20s_B%20%3D%20%5Cfrac%7B4%7D%7B%5Csqrt%7B100%7D%7D%20%3D%200.4)
For the distribution of differences, we have that:
![\overline{x} = \mu_A - \mu_B = 73 - 74 = -1](https://tex.z-dn.net/?f=%5Coverline%7Bx%7D%20%3D%20%5Cmu_A%20-%20%5Cmu_B%20%3D%2073%20-%2074%20%3D%20-1)
![s = \sqrt{s_A^2 + s_B^2} = \sqrt{0.2^2 + 0.4^2} = 0.447](https://tex.z-dn.net/?f=s%20%3D%20%5Csqrt%7Bs_A%5E2%20%2B%20s_B%5E2%7D%20%3D%20%5Csqrt%7B0.2%5E2%20%2B%200.4%5E2%7D%20%3D%200.447)
<h3>What is the test statistic?</h3>
It is given by:
![t = \frac{\overline{x} - \mu}{s}](https://tex.z-dn.net/?f=t%20%3D%20%5Cfrac%7B%5Coverline%7Bx%7D%20-%20%5Cmu%7D%7Bs%7D)
In which
is the value tested at the null hypothesis.
Hence:
![t = \frac{\overline{x} - \mu}{s}](https://tex.z-dn.net/?f=t%20%3D%20%5Cfrac%7B%5Coverline%7Bx%7D%20-%20%5Cmu%7D%7Bs%7D)
![t = \frac{-1 - 0}{0.447}](https://tex.z-dn.net/?f=t%20%3D%20%5Cfrac%7B-1%20-%200%7D%7B0.447%7D)
![t = -2.24](https://tex.z-dn.net/?f=t%20%3D%20-2.24)
<h3>What is the p-value and the decision?</h3>
Considering a one-tailed test, as stated in the exercise, with 100 - 1 = 99 df, using a t-distribution calculator, the p-value is of 0.014.
Since the p-value is less than the significance level of 0.05, it is found that there is a significant difference between the wait times for the two populations.
More can be learned about the t-distribution at brainly.com/question/16313918