Testing the hypothesis, it is found that:
a)
The null hypothesis is: ![H_0: \mu \leq 10](https://tex.z-dn.net/?f=H_0%3A%20%5Cmu%20%5Cleq%2010)
The alternative hypothesis is: ![H_1: \mu > 10](https://tex.z-dn.net/?f=H_1%3A%20%5Cmu%20%3E%2010)
b)
The critical value is: ![t_c = 1.74](https://tex.z-dn.net/?f=t_c%20%3D%201.74)
The decision rule is:
- If t < 1.74, we <u>do not reject</u> the null hypothesis.
- If t > 1.74, we <u>reject</u> the null hypothesis.
c)
Since t = 1.41 < 1.74, we <u>do not reject the null hypothesis</u>, that is, it cannot be concluded that the mean weight loss is of more than 10 pounds.
Item a:
At the null hypothesis, it is tested if the mean loss is of <u>at most 10 pounds</u>, that is:
![H_0: \mu \leq 10](https://tex.z-dn.net/?f=H_0%3A%20%5Cmu%20%5Cleq%2010)
At the alternative hypothesis, it is tested if the mean loss is of <u>more than 10 pounds</u>, that is:
![H_1: \mu > 10](https://tex.z-dn.net/?f=H_1%3A%20%5Cmu%20%3E%2010)
Item b:
We are having a right-tailed test, as we are testing if the mean is more than a value, with a <u>significance level of 0.05</u> and 18 - 1 = <u>17 df.</u>
Hence, using a calculator for the t-distribution, the critical value is:
.
Hence, the decision rule is:
- If t < 1.74, we <u>do not reject</u> the null hypothesis.
- If t > 1.74, we <u>reject</u> the null hypothesis.
Item c:
We have the <u>standard deviation for the sample</u>, hence the t-distribution is used. The test statistic is given by:
The parameters are:
is the sample mean.
is the value tested at the null hypothesis.
- s is the standard deviation of the sample.
- n is the sample size.
For this problem, we have that:
![\overline{x} = 10.8, \mu = 10, s = 2.4, n = 18](https://tex.z-dn.net/?f=%5Coverline%7Bx%7D%20%3D%2010.8%2C%20%5Cmu%20%3D%2010%2C%20s%20%3D%202.4%2C%20n%20%3D%2018)
Thus, the value of the test statistic is:
![t = \frac{\overline{x} - \mu}{\frac{s}{\sqrt{n}}}](https://tex.z-dn.net/?f=t%20%3D%20%5Cfrac%7B%5Coverline%7Bx%7D%20-%20%5Cmu%7D%7B%5Cfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%7D%7D)
![t = \frac{10.8 - 10}{\frac{2.4}{\sqrt{18}}}](https://tex.z-dn.net/?f=t%20%3D%20%5Cfrac%7B10.8%20-%2010%7D%7B%5Cfrac%7B2.4%7D%7B%5Csqrt%7B18%7D%7D%7D)
![t = 1.41](https://tex.z-dn.net/?f=t%20%3D%201.41)
Since t = 1.41 < 1.74, we <u>do not reject the null hypothesis</u>, that is, it cannot be concluded that the mean weight loss is of more than 10 pounds.
A similar problem is given at brainly.com/question/25147864