Download 1) Determine whether the distribution represents a probability

Mat 157/BusAd 221
Homework 3
Due 6/22/12 by 5pm
Name___________________________________
1) Determine
whether the distribution represents a probability distribution.
If not, identify any requirements that are not satisfied.
x
3
6
9
12
15
P(x)
-0.3
0.5
0.1
0.3
0.4
2) The
random variable X represents the number of credit cards that adults
have along with the corresponding probabilities. Find the expected value
of X.
X
0
1
2
3
4
1)
2)
P(X=x)
0.07
0.68
0.21
0.03
0.01
3) Assume
that male and female births are equally likely and that the birth
of any child does not affect the probability of the gender of any other
children. Find the probability of exactly two boys in three births.
1
3)
4) The
probability that an individual is left-handed is 0.11. In a class of 40
students, what is the probability of finding two left-handers?
4)
5) Assume
5)
that male and female births are equally likely and that the birth
of any child does not affect the probability of the gender of any other
children. Suppose that 800 couples each have a baby; find the mean and
standard deviation for the number of girls in the 800 babies.
6) Find
the area of the indicated region under the standard normal curve.
A) 0.0968
7) Find
B) 0.9032
C) 0.0823
D) 0.4032
the area of the indicated region under the standard normal curve.
A) 0.309
B) 1.309
C) 0.6562
2
6)
D) 0.3438
7)
8) Find
the area of the indicated region under the standard normal curve.
A) 0.9177
B) 0.9032
C) 0.0823
D) 0.0968
9) An
airline knows from experience that the distribution of the number of
suitcases that get lost each week on a certain route is approximately normal with
µ = 15.5 and σ = 3.6. What is the probability that during a given week the airline
will lose more than 20 suitcases?
A) 0.3944
B) 0.1056
C) 0.4040
that the salaries of elementary school teachers in the United States are
normally distributed with a mean of $32,000 and a standard deviation of $3000.
If a teacher is selected at random, find the probability that he or she makes more
than $36,000.
B) 0.1056
C) 0.4040
3
9)
D) 0.8944
10) Assume
A) 0.0918
8)
D) 0.9082
10)