Ch15 Linear Transformations and Combinations Classwork
1.
A study of how well freshmen adapt the first six weeks of the school year was done. 50 randomly selected 9
th
graders office referral
records were examined to determine how often the ninth graders needed administrative guidance to a positive road to follow on campus.
# of referrals, x
0
1
2
3
4
5
6
P(X = x)
.46
.22
.12
.10
.06
.02
.02
a. What is the expected number of referrals?
b. What is the variance and standard deviation of number of referrals? If we add 7 to the list of x above and then multiply it by -2 then:
c. What is the new mean number of referrals?
d. What is the new variance and standard deviation?
2. Suppose the equation Y = 200 + 10X converts a PSAT math score, X, into an SAT math score, Y.
Suppose the average PSAT math score is
48 with a standard deviation of 1.5.

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