STAT 351 Chapter 4A
In a histogram, the proportion of the total area which must be to the left of the median is: a. exactly 0.50. b. less than 0.50 if the distribution is negatively skewed. c. more than 0.50 if the distribution is positively skewed. d. unknown.
A
The mean is affected by extreme values but the median is not.
T
Another word for the mean of a data set is the
average
The sample mean is denoted by ____________________ and the population mean is denoted by ____________________.
x-bar, mu
The average score for a class of 30 students was 75. The 15 male students in the class averaged 70. The 15 female students in the class averaged: a. 85. c. 75 b. 80 d. 70
B
In a histogram, the proportion of the total area which must be to the left of the median is more than 0.50 if the distribution is positively skewed.
F
If the mean, median, and mode are all equal, the histogram must be symmetric and bell shaped.
T
In a bell shaped distribution, there is no difference in the values of the mean, median, and mode
T
In a histogram, the proportion of the total area which must be to the right of the mean is exactly 0.50 if the distribution is symmetric and unimodal.
T
In a negatively skewed distribution, the mean is smaller than the median and the median is smaller than the mode.
T
Suppose a sample of size 50 has a sample mean of 20. In this case, the sum of all observations in the sample is 1,000.
T
The size of a sample is denoted by the letter ____________________ and the size of a population is denoted by the letter ____________________.
n, N
The median of a set of data is more representative than the mean when the mean is larger than most of the observations.
T
The median of an ordered data set with 30 items would be the average of the 15th and the 16th observations.
T
The value of the mean times the number of observations equals the sum of the observations
T
mu is a population parameter and xbar is a sample statistic.
T
The ____________________ is calculated by finding the middle of the data set, when the data are ordered from smallest to largest.
median
The ____________________ is not as sensitive to extreme values as the ____________________.
median, mean
The ____________________ is the least desirable of all the measures of central location.
mode
Which of the following statements about the median is not true? a. It is more affected by extreme values than the mean. b. It is a measure of central location. c. It is equal to Q2. d. It is equal to the mode in a bell shaped distribution.
A
Which of the following statements is true for the following observations: 9, 8, 7, 9, 6, 11, and 13? a. The mean, median, and mode are all equal. b. Only the mean and median are equal. c. Only the mean and mode are equal d. Only the median and mode are equal.
A
The mean is a measure of variability.
F
In a positively skewed distribution: a. the median equals the mean. b. the median is less than the mean. c. the median is larger than the mean. d. the mean can be larger or smaller than the median.
B
Which of the following statements about the mean is not always correct? a. The sum of the deviations from the mean is zero. b. Half of the observations are on either side of the mean. c. The mean is a measure of the central location. d. The value of the mean times the number of observations equals the sum of all observations.
B
Which of these measures of central location is not sensitive to extreme values? a. The mean c. The mode b. The median d. All of these choices are true.
B
Which measure of central location can be used for both interval and nominal variables? a. The mean c. The mode b. The median d. All of these choices are true.
C
Which measure(s) of central location is/are meaningful when the data are ordinal? a. The mean and median b. The mean and mode c. The median and mode d. Only mean
C
Which of the following statements is true? a. When the distribution is positively skewed, mean < median < mode. b. When the distribution is negatively skewed, mean > median > mode. c. When the distribution is symmetric and unimodal, mean = median = mode. d. When the distribution is symmetric and bimodal, mean = median = mode.
C
Which of the following summary measures is sensitive to extreme values? a. The median c. The mean b. The interquartile range d. The first quartile
C
In a histogram, the proportion of the total area which must be to the left of the median is less than 0.50 if the distribution is negatively skewed.
F
In a histogram, the proportion of the total area which must be to the right of the mean is: a. less than 0.50 if the distribution is negatively skewed. b. exactly 0.50. c. more than 0.50 if the distribution is positively skewed. d. exactly 0.50 if the distribution is symmetric and unimodal.
D
In a perfectly symmetric bell shaped "normal" distribution: a. the mean equals the median. c. the mean equals the mode. b. the median equals the mode. d. All of these choices are true.
D
Which of the following statistics is a measure of central location? a. The mean c. The mode b. The median d. All of these choices are true.
D
A data sample has a mean of 107, a median of 122, and a mode of 134. The distribution of the data is positively skewed.
F
There are three measures of central location; the mean, the ____________________, and the ____________________.
median, mode
