Deck 7: Measures of Dispersion

Question 1

The mean is an example of a measure of dispersion.

Answer 1

False

Question 2

Frequency distributions describe the range and frequency of a variable's values.

Answer 2

True

Question 3

Frequency distributions are readily calculated by statistical software programs.

Answer 3

True

Question 4

A histogram is similar to a stem-and-leaf plot but differs in that it shows the number of observations in each category.

Question 5

When recoding continuous variables into ordinal-level variables, the width of categories should be equal, unless compelling reasons exist to do otherwise.

Question 6

Pie charts are graphs that show the frequency of occurrences through stacks.

Question 7

Visual representation is important for analysis and in the communication of study findings to a broader audience.

Question 8

Boxplots are used for preliminary data analysis.

Question 9

The boxplot is used with ordinal-level data.

Question 10

The interquartile range is defined as the distance between the first and third quartiles.

Question 11

Values above the upper fence are defined as outliers in boxplots.

Question 12

The inner fence is an observed value.

Question 13

Observations flagged as outliers generally should be retained when they are not coding errors, when they are plausible values of the variable in question, and when they do not greatly affect the value of the mean.

Question 14

The normal distribution refers to the distribution of a variable that resembles a cigar-shaped curve.

Question 15

The standard deviation is a desirable statistic because metric variables are normally distributed.

Question 16

When variables are normally distributed, about 95% of observations lie ±5 standard deviations from the mean.

Question 17

Standardized variables have a mean of zero and a standard deviation of 1.

Question 18

Skewness is a measure of whether the peak is centered in the middle of the distribution.