QMB 3200 Final Exam Questions and
Answers 100% Verified
Suppose we have the following data: 12, 17, 13, 25, 16, 21, 30, 14, 16, and 18. To find
the 10% trimmed mean, what numbers should be deleted from the calculation? -
ANSWER-12 and 30
Which of the following is not resistant to the outliers in a data set?
a. Median
b. Mean
c. Variance
d. Interquartile range - ANSWER-b. mean
The pth percentile is a value such that at least p percent of the observations are: -
ANSWER-less than or equal to this value.
Which of the following provides a measure of central location for the data?
a. Mean
b. Variance
c. Mode
d. Standard deviation - ANSWER-a. mean
When testing water for chemical impurities, results are often reported as BDL, that is,
below detection limit. The following data set gives the measurements of the amount of
lead in a series of water samples taken from inner-city households (ppm):
5, 7, 12, BDL, 10, 8, BDL, 20, 6
Which of the following is correct?
a. The mean lead level in the water is about 10 ppm.
b. The median lead level in the water is 8 ppm.
c. The mean lead level in the water is about 8 ppm.
d. The median lead level in the water is 7 ppm. - ANSWER-d. The median lead level in
the water is 7 ppm.
A student made scores of 85, 56, and 91 on her first three statistics tests. What score
does she need to make on her next test to have an 80 test average? - ANSWER-88
Growth factors for the population of Dallas in the past five years have been 1, 2, 3, 4,
and 5, respectively. The geometric mean is: - ANSWER-^5square root 120
A sample of 99 distances has a mean of 24 feet and a median of 21.5 feet.
Unfortunately, it has just been discovered that an observation that was erroneously
, There are three executives in an office with age 56, 57, and 58. If a 57-year-old
executive enters the room, then: - ANSWER-the mean age will stay the same, but the
variance will decrease.
The difference between the largest and the smallest data values is the: - ANSWER-
range
The interquartile range is: - ANSWER-the difference between Q3 and Q1, the third and
first quartiles.
The standard deviation of a sample was reported to be 20. The report indicated that Σ
(xi-x̄)^2 = 7200. What is the sample size? - ANSWER-20-1 = 19
recorded as "30" actually had a value of "35." If we make this correction to the data,
then: - ANSWER-the median remains the same, but the mean is increased.
A numerical value used as a summary measure for a sample, such as sample mean, is
known as a: - ANSWER-sample statistic.
The measure of location that is most likely to be influenced by extreme values in a data
set is the: - ANSWER-mean
A student was performing an experiment that compared a new high protein food to the
old food for pigs. He found the mean weight gain for subjects consuming the new food
to be 12.8 pounds with a standard deviation of 3.5 pounds. Later, he realized that the
scale was out of calibration by 1.5 pounds (meaning that the scale weighed items 1.5
pounds more). What should be the summary measures, mean and standard deviation,
for the subjects consuming the new food? - ANSWER-The mean should be 11.3 and
the standard deviation should remain unchanged.
When a set of data has suspect outliers, which of the following is the referred measure
of central tendency? - ANSWER-median
In a sample of 500 students whose mean height is 67.8 inches, 150 were women. If the
mean height of the women was 63.0 inches, what is the mean height of the men in the
sample? - ANSWER-69.9
The coefficient of variation formula - ANSWER-the standard deviation divided by the
mean and multiplied by 100.
The summary statistics for the hourly wages of a sample of 130 system analysts are
given below:
Mean = 60
Range = 20
Mode = 73
