vdoc

Test Questions 13
68. Determine the standard deviation of the following sample data:
A. 3
B. 2
C. 4.58
D. 20.95
{16, 18, 20, 15, 25, 23, 27}
69. An instructor finds the mean and standard deviation of final test scores to be 65
and 9, respectively. She feels the scores are low and she decides to give five bonus
points to each student. Determine how the mean and standard deviation will be
affected.
A. Both the mean and standard deviation will increase.
B. The mean will increase but the standard deviation will decrease.
C. The mean will increase but the standard deviation will remain the same.
D. Both the mean and standard deviation will remain the same.
70. The diameter of the soccer balls manufactured by a company follow a normal
distribution with a mean of 22.5 cm and standard deviation of 0.25 cm. A player
bought a new soccer ball with a diameter of 23 cm. Find the z-score of the diameter
of the new soccer ball.
A. 2
B. 1
C. –2
D. –1
71. A sample of 25 data points has a mean equal to 40 and a standard deviation equal
to 5. How would adding five additional data points, each with a value of 40, affect
the values of the mean and standard deviation?
A. Both the mean and standard deviation would increase.
B. The mean would increase but the standard deviation would decrease.
C. The mean would increase but the standard deviation would remain the same.
D. Both the mean and standard deviation would remain the same.
72. Women’s heights follow a normal distribution with a mean of 65 inches and
a standard deviation of 2.5 inches. Elizabeth is 5 feet 5 inches tall. What is
Elizabeth’s z-score? What is the percentile of her height?
A. 1, 84
B. –1, 16
C. 0, 50
D. 2, 98