1. A certain Board of Trustees consists of 9 members. Each year, they elect a 3-person
committee to oversee buildings and grounds. When the board elects the buildings and
grounds committee, how many 3
PRACTICE EXAM 2
STAT 380
1. The heights of students are normally distributed with a mean of 174.5 centimeters and a
standard deviation of 6.9 centimeters. How many of 1000 students would you expect to
STAT 380
Exam 1
Friday, February 9
1. Suppose we randomly select five recordings of classical music from the
Schwann Record Catalog and determine the listening time for each.
The data values (rounded
STAT 380/880
Homework 2
1. Assume the pdf of X is given by
(
f (x) =
3 2
27 x
0
for 0 x c
otherwise
a. Find c and verify that this is a pdf.
Solution:
Zc
3 2
x dx c3 = 27 c = 3
27
0
Verify that this i
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Homework 5
due Monday, April 3
1. Use the t-table (Table A.4) to find the following.
a. t.10 when = 12.
Solution: t.10 =1.356.
b. t.025 when = 15.
Solution: t.025 = -2.131.
c. P (T < .906
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Homework 4 Solutions
1. Compute the following probabilities:
a. P (Z 1.75)
Solution: P (Z 1.75) = .9599
b. P (Z > 1.75)
Solution: P (Z > 1.75) = .0401
c. P (Z 1.75)
Solution: P (Z 1.75) =
STAT 380/880
Homework 3
1. Let X be a binomial random variable with E(X) = 2 and V ar(X) =
1.6.
a. Find P (X = 2) using the binomial pmf (work out by hand).
Solution: Since E(X) = np = 2 and V ar(X) =