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Finding Normal Probabilities

Total questions: 11

Worksheet time: 20mins

Name
Class
Date
1.
What shape is a normal distribution curve?
a)
Half curve
b)
Round curve
c)
Bell curve
d)
Square curve
2.
Find the area below a z-score of 1.25. 
a)
0.89
b)
0.01
c)
0.79
d)
0.12
3.
Find the area of the shaded region. 
a)
0.16
b)
0.84
c)
0.68
d)
0.34
4.
If heights of 3rd graders follow a normal distribution with a mean of 52 inches and a standard deviation of 2.5 inches, what is the z score of a 3rd grader who is 47 inches tall? 
a)
-5
b)
-2
c)
2
d)
5
5.
Find the area under the normal distribution curve between a z=-1.26 and z=.57. 
a)
0.0047
b)
0.9204
c)
0.6119
d)
0.4981
6.
The weights of adult male beagles are normally distributed, with a mean of 25 pounds and a standard deviation of 3 pounds. A beagle is randomly selected. Find the probability that the beagle’s weight is less than 24 pounds.
a)
0.3694
b)
0.3781
c)
0.0912
7.
The test scores for the exam in statistics class have a mean of 78 points and standard deviation of 9 points. A student is randomly selected. Assuming the scores are normally distributed find the probability that the score is more than 95. 
a)
0.0295
b)
0.00000005
c)
0.3209
d)
4.32
8.
μ = 350 , σ = 20 , find P(X > 400)
a)
0.0062
b)
0.9938
c)
0.4013
d)
0.5987
9.
The mean GPA of students in a course at UCDavis is 3.2 with a standard deviation of 0.3. What percent of students in the course have a GPA between 2.9 and 3.8? 
a)
81.85%
b)
47.5%
c)
68%
d)
95%
10.

The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a standard

deviation of 15 days. Find the probability of a pregnancy lasting more than 300 days.

a)

0.0166

b)

0.9834

c)

0.2375

d)

0.3189

11.

Assume 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.

a)

0.9802

b)

0.2113

c)

0.0918

d)

0.9827