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# Normal distribution

1)Which choice is another term that can be used to describe a normal distribution:
A) discrete distribution
B) negatively or positively skewed
C) bell curve
D) independent variable

2) If a normal distribution has a mean of 30 and a standard deviation of 5, then
A) the median is 35 and the mode is 25.
B) the median is 30 and the mode is 30.
C) the median is 30 and the mode is 35.
D) the median is 25 and the mode is 35.

3) Find the probability P(z < 0.37) using the standard normal distribution.
A) 0.6443
B) 0.6300
C) 0.1443
D) 0.3557

4) Find the area under the standard normal distribution curve between z = -2.05 and z = 2.05.
A) 0.9876
B) 0.4938
C) 0.4798
D) 0.9596

5) Find the probability P(-0.72 < z < -0.11) using the standard normal distribution
A) 0.7796
B) 0.2204
C) 0.0900
D) 0.3504

6) In a standard normal distribution, what z value corresponds to 17% of the data between the mean and the z value?
A) 0.52
B) 2.10
C) 0.44
D) 1.25

7)Find the z value to the right of the mean such that 85% of the total area under the standard normal distribution curve lies to the left of it?

8) If a normally distributed group of test scores have a mean of 70 and a standard deviation of 12, find the percentage of scores that will fall below 50.
A) 45.25%
B) 6.75%
C) 35.54%
D) 4.75%

9) The average hourly wage of workers at a car wash is \$6.50/hr. Assume the wages are normally distributed with a standard deviation of \$0.45. If a worker at this car wash is selected at random, what is the probability that the worker earns more than \$6.75
A) 27.6%
B) 5.2%
C) 28.8%
D) 42.1%

#### Solution Preview

1) Which choice is another term that can be used to describe a normal distribution:

Ans: C) bell curve
Explanation: A normal distribution is a bell shaped curve.

2) If a normal distribution has a mean of 30 and a standard deviation of 5, then

Ans: B) the median is 30 and the mode is 30.
Explanation: For a normal distribution Mean = Median = Mode.

3) Find the probability P(z < 0.37) using the standard normal distribution.

Ans: A) 0.6443
Explanation: Using the Excel function =NORMSDIST(0.37) we get P(z < 0.37) as 0.6443

4) Find the area under the standard normal distribution curve between ...

#### Solution Summary

The solution provides detailed explanation of some objective type problems from Normal distribution.

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