Ch. 6.1 #7-49 odd

c) 1%
For total area = 0.01, there will be area = 0.005 in each tail. The z scores are z= 2.58.
Section 6-2 # 1, 2, 9, 11, 15, 21, 22, 23, 26, 28, 30
1. Admission Charges for Movies The average admission charge for a movie is $5.81. If the
distribution of movie admission charges is approximately normal with a standard deviation of $0.81, what
is the probability that a randomly selected admission charge is less than $3.50?
X
$3.50 $5.81
z 2.85
$0.81
then look up z = -2.85 in Table E and you get that the area = 0.0022 or 0.22%
Pz ( 2.85) 0.0022 or 0.22%
-2.85 0
2. Teachers’ Salaries The average annual salary for all U.S. teachers is $47,750. Assume that the
distribution is normal and the standard deviation is $5680. Find the probability that a randomly selected
teacher earns
a. Between $35,000 and $45,000 a year
X
35,000 47,750
z 2.24
5680
45,000 47,750
z
0.48
5680
P( 2.24 z 0.62) 0.3156 0.0125 0.3031 or 30.31%