Since the basis is from year 1 to year 2, calculate first for the difference of their percentages. That would be:
Difference = year 2 - year 1
Difference = 2.32% - 1.1% = 1.22%
We apply this same value of percentage increase from year 2 to year. Thus, the percentage for year 3 is:
% Year 3 = % Year 2 + percentage increase
% Year 3 = 2.32% + 1.22%
% Year 3 = 3.54%
Let m and s be the number of math and sociology books sold respectively.
m=s+88 we are also told that:
m+s=426, using m found above in this equation gives you:
s+88+s=426 combine like terms on left side
2s+88=426 subtract 88 from both sides
2s=338 divide both sides by 2
s=169, since m=s+88
m=169+88=257
So 257 math and 169 sociology textbooks were sold.
I got C for 6 & 7. I haven't done this in a while so I don't know 8 & 9. I hope I helped!
Using the z-distribution, the 99% confidence interval to estimate the population proportion is: (0.2364, 0.4836).
<h3>What is a confidence interval of proportions?</h3>
A confidence interval of proportions is given by:

In which:
is the sample proportion.
In this problem, we have a 99% confidence level, hence
, z is the value of Z that has a p-value of
, so the critical value is z = 2.575.
The estimate and the sample size are given by:
.
Then the bounds of the interval are:
The 99% confidence interval to estimate the population proportion is: (0.2364, 0.4836).
More can be learned about the z-distribution at brainly.com/question/25890103
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