Please show your work. I am having trouble working out the problems. I would like as detailed an explaination for the answers as you can give.

1. A teacher gives a 20-point quiz to 10 students. The scores are listed below. What percentile corresponds to the score of 12?

20 8 10 7 15 16 12 19 14 9

A. 13

B. 40

C. 25

D. 12

My answer...
1) The ten values, in order, are:

7, 8, 9, 10, 12, 14, 15, 16, 19, 20

The value 12 is the fifth value:

5/10 = 0.5 = 50%

But this does not match any of the listed answer values,

2) A data set contains the observations 3, 6, 7, 2, 8. Find Σx 2 -Σx 25 .

A. 129.6

B. 297.2

C. 540.8

D. 26.8

I have no idea how to get this

3)Merchants are always interested in determining why a customer selected their store to make a purchase. Best Sportswear Boutique conducted a customer survey to determine why its customers shopped at the store. The results are shown in the figure. What proportion of customers responded that merchandise was the reason they shopped at the store?

A.27

B.37

C. 12

D. 30

**See number 30 on the picture enclosed**

My answer....
20 + 30 + 10 + 10 = 70 interviewed

30 chose "merchandise"

30/70 = 3/7 = 0.4285714286....

This does not match any of the listed options. Please help.

1. A social psychologist has developed a test measure gregariousness. The test is normed so that it has a mean of 70 and a standard deviation of 20, and the gregariousness scores are normally distributed in the population of college students used to develop the test.
a. What is the percentile rank of a score of 40?
b. What

Discrete math questions. Please provide formulas and all calculations for all 22. They are very short answer type questions.
2. Write the first four terms of the sequence defined by bj = 1 + 2j, for all integers j 0.
b0 =
b1 =
b2 =
b3 =
14. Find an explicit formula for the sequence with the

Summation of indexed data
The following is a list of 14 measurements:
-70, -95, -14, -4, 22, -42, -56, 82, 99, 32, -57, 34, -39, -6
Suppose that these 14 measurements are respectively labeled X1, X2, .........., X14
(Thus -70 is labeled X1, -95 is labeled X2 and so on)
Find Summation (Xi/9)
Round your answer

Tthe mean for a special distribution is 100 and the standard deviation is 15. What is the estimated percentile for an individual who had a score of 90 on this scale?

Week 2 Problem Sets
2. a 9
b 31
c 119
4. 54-59
50-55
45-49
40-44
35-39
30-34
25-29
20-24
15-19
10-14
6. When we generate a large volume of data, we are unlikely to be able to make sense of it by looking at all the data. The largest amount o

1. Ten observations of X are
67 6 7 35 78 28 74 5 9 37
a) Find the order statistics
b) Find the median and 80th percentile of the sample
c) Determine the first and third quartiles of the sample
2. Let Y1