Find the rate of change, (y2-y1)/(x2-x1), from the data given...
(2.16-1.26)/(12-7)=0.18
(1.26-0.72)/(7-4)=0.18
Since the rate is constant, this is a linear equation of the form y=mx+b. Furthermore, since 0 pencils cost 0, b=0, so the cost of the pencils is simply the number of pencils times 18 cents...
c(p)=0.18p (cost with respect to pencils is 0.18 times the number of pencils)
Answer:
The null and alternative hypotheses are:


Under the null hypothesis, the test statistic is:

Where:
is the sample mean
is the sample standard deviation
is the sample size


Now, we can find the right tailed t critical value at 0.01 significance level for df = n-1 = 10 - 1 = 9 using the t distribution table. The t critical value is given below:
Since the test statistic is less than the t critical value, we therefore, fail to reject the null hypothesis and conclude that there is not sufficient evidence to support the claim that the people do better with the new edition.
uhm i think its 15 cause you just add them all i guess