Answer:
The decision rule is
Reject the null hypothesis
The conclusion is
There is sufficient evidence to reject the claim
Step-by-step explanation:
From the question we are told that
The population mean is ![\mu = 24.2 \ gallons \ per \ year](https://tex.z-dn.net/?f=%5Cmu%20%3D%20%2024.2%20%5C%20gallons%20%5C%20per%20%5C%20year)
The sample size is n = 101
The sample mean is
The standard deviation is ![\sigma = 3.2 \ gallons](https://tex.z-dn.net/?f=%5Csigma%20%20%3D%20%203.2%20%5C%20gallons)
The null hypothesis is ![H_o : \mu = 24.2](https://tex.z-dn.net/?f=H_o%20%20%3A%20%20%5Cmu%20%3D%20%2024.2)
The alternative hypothesis is ![H_a : \mu \ne 24.2](https://tex.z-dn.net/?f=H_a%20%3A%20%20%5Cmu%20%5Cne%2024.2)
Generally the test statistics is mathematically represented as
![z = \frac{ \= x - \mu }{ \frac{\sigma }{ \sqrt{n} } }](https://tex.z-dn.net/?f=z%20%3D%20%20%5Cfrac%7B%20%5C%3D%20x%20-%20%5Cmu%20%7D%7B%20%5Cfrac%7B%5Csigma%20%7D%7B%20%5Csqrt%7Bn%7D%20%7D%20%7D)
=>
=> ![z = -2.198](https://tex.z-dn.net/?f=z%20%3D%20-2.198)
From the z table the area under the normal curve to the left corresponding to -2.198 is
![P(Z < -2.198 ) = 0.013975](https://tex.z-dn.net/?f=P%28Z%20%3C%20%20-2.198%20%29%20%20%3D%20%20%200.013975)
Gnerally the p-value is mathematically represented as
=>
From the value obtained we have that
hence
The decision rule is
Reject the null hypothesis
The conclusion is
There is sufficient evidence to reject the claim
Using the Rejection Regions for a z-test method
Generally from the z table the critical value of
is
![z_{critical} = \pm 1.96](https://tex.z-dn.net/?f=z_%7Bcritical%7D%20%3D%20%20%5Cpm%201.96)
Not we are using
because it is a two - tailed test
Now comparing the critical value and the test statistics we see that the
region covered by the test statistics (i.e
) is greater than the region covered by the critical value (i.e
)
Hence
The decision rule is
Reject the null hypothesis
The conclusion is
There is sufficient evidence to reject the claim