Measures of location and dispersion.
1) Which of the following is NOT true regarding the normal probability distribution?
a. 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 X-axis at z = -3 and z = 3
e. None of the above
2) Which of the following is not a characteristic of the normal probability distribution?
a. Positively skewed
b. Bell-shaped
c. Symmetrical
d. Asymptotic
e. All of the above
3) Which announcement about bar charts and histograms is false?
a. Histograms have no spaces between the bars.
b. Histograms show how a quantitative variable is distributed while bar charts show counts (or percents) for different categories of a categorical variable.
c. Histograms are just a special kind of bar chart.
d. Histograms and bar charts are the same thing.
e. Histograms always have a numerical scale on the x-axis.
4) Which is true of positively skewed distribution?
a. The right tail is shorter
b. The left tail is shorter
c. The right tail is longer
d. It has no tail
5) In a right-skewed distribution
a. The median is greater than the mean
b. The mode is equal to the mean and median
c. The median is less than the mean
d. The mean is less than the mode
6) In positively skewed distributions
a. Have few extremely high values
b. Have significantly low values
c. The mass is concentrated on the right of the distribution
d. None of above is true
7) In a negatively skewed distribution
a. the left tail is longer
b. the right tail is longer
c. the left tail is shorter
d. has no tail
8) In a left-skewed distribution
a. the mean is greater than the median
b. the mean, median and mode are the same
c. the mean is lower than the median
d. the mode is less than the median
9) Which is not true of perfectly symmetrical distributions?
a. the mean, median and mode are the same
b. it has mirror symmetry
c. the tails on either side touches the x-axis
d. They are uni-modal.
10) "Skewness" means that the distribution of data is
a. Incorrect
b. Has extreme values
c. Symmetrical
d. Lumpy in the middle
e. None of the above