The
formula , where r! is 1*2*3*...r
is the formula which gives us the total number of ways of forming groups of r objects out of n objects.
for example, given 10 objects, there are C(10,6) ways of forming groups of 6, out of the 10 objects.
<span>Thus, there are C(6, 3) many ways of forming different triples out of 6.</span>
Answer: A.20
Testing the hypothesis in this problem which is a two-tailed test, we can conclude that there is not sufficient evidence to conclude that the mean time of installation has changed, since the p-value of the test is 0.0364 > 0.01,
At the null hypothesis, we test if the <u>mean is of 25 minutes</u>, that is:
At the alternative hypothesis, we test if the mean has changed, that is, if it is <u>different than 25 minutes</u>.
We have the <u>standard deviation for the sample</u>, thus, the t-distribution is used. The value of the test statistic is:
In which:
In this problem:
The <u>value of the test statistic</u> is:
Since the p-value of the test is 0.0364 > 0.01, there is not sufficient evidence to conclude that the mean time of installation has changed.
A similar problem is given at brainly.com/question/23777908