Using the t-distribution, it is found that the test statistic for the hypotheses test is given by:

<h3>What are the hypotheses tested?</h3>
At the null hypotheses, it i tested if the mean difference remains the same, that is:

At the alternative hypotheses, it is tested if it has decreased, hence:
.
<h3>What is the test statistic?</h3>
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.
The parameters are given as follows:
.
Hence the test statistic is given by:


More can be learned about the t-distribution at brainly.com/question/16162795
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Answer:ACTUAL
Step-by-step explanation:
2 1/2 miles = 1/6 hours
2 1/2 miles * 6 = 1/6 hours * 6
12 1/2 miles = 6/6 hours
12 1/2 miles = 1 hour
12 1/2 miles/hr
Answer:
B) 3.5cm
Step-by-step explanation:
1/80 = n/280
1 * 280 = n * 80
280 = 80n
3.5 = n or n = 3.5