1. Which of the following statements regarding the normal distribution is NOT true?
A) The mean, median and mode are all equal.
B) It has a single peak.
C) It is symmetrical.
D) The points of the curve meet the Xaxis at z = 3 and z = 3.
E) All of the above are true.
2. The mean of a normally distributed group of weekly incomes of a large group of executives is
$1,000 and the standard deviation is $100. What is the zscore for an income of $1,100?
A) 1.00
B) 2.00
C) 1.683
D) 0.90
E) None of the above
3. BallBearings, Inc. produces ball bearings automatically on a Kronar BBX machine. For one
of the ball bearings, the mean diameter is set at 20.00 mm (millimeters). The standard deviation
of the production over a long period of time was computed to be 0.150 mm. What percentage of
the ball bearings will have diameters 20.27 mm or less? (Assume a normal population).
A) 41.00%
B) 12.62%
C) 96.41%
D) 85.00%
E) 3.59%
4. The average score of 100 students taking a statistics final was 70 with a standard deviation of
7. Assuming a normal distribution, what proportion of the students scored 90 or higher?
A) 0.4979
B) 0.0021
C) 0.9979
D) 2.86
E) None of the above
5. What is the area under the normal curve between z = 1.0 and z = 2.0?
A) 0.0228
B) 0.3413
C) 0.1359
D) 0.4772
E) None of the above
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document6. Past experience of a large manufacturing firm with administering a test to recent college
graduates who had applied for a job revealed that the mean test score was 500, and the standard
deviation was 50. The distribution of the test scores was normal. Based on this experience,
management is considering placing a person whose score is in the upper 6 percent of the
distribution directly into a responsible position. What is the lowest score a college graduate must
earn to qualify for a responsible position?
A) 50
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '10
 BARCUS
 Normal Distribution, Standard Deviation

Click to edit the document details