Displaying Quantitative Data

Question 1

Distribution

Answer 1

…slices up all the possible values of a quantitative variable into equal-width bins and gives the number of values (or counts) falling into each bin.

Question 2

Histogram

Answer 2

Uses adjacent bars to show quantitative distribution by representing the frequency of values falling into each bin.

Question 3

Relative Frequency Histogram

Answer 3

A relative frequency histogram uses adjacent bars to show the relative frequency of quantitative values falling in each bin.

Question 4

Gap

Answer 4

A region of the distribution where there are no values.

Question 5

Stem-and-leaf display

Answer 5

A display that shows quantitative data values in a way that sketches the distribution of the data by separating the first digit with a bar as a label on the left. On the right are lists of digits, one digit for each value in that bin.

Question 6

Dotplot

Answer 6

Graphs a dot for each case against a single axis.

Question 7

Shape

Answer 7

To describe this charcteristic of a distribution, look for (1) single vs. multiple modes, (2) symmetry vs. skewness, and (3) outliers and gaps.

Question 8

Mode

Answer 8

A hump or local high point in the shape of the distribution of a variable. The apparent location can change as the scale of a histogram is changed.

Question 9

Unimodal

Answer 9

Having one mode. Describes the shape of a histogram when it’s generally mound-shaped.

Question 10

Bimodal

Answer 10

Having two modes. Describes the shape of a histogram when it has two humps or mounds.

Question 11

Multimodal

Answer 11

Having more than two modes. Describes the shape of a histogram when it has more than two humps or mounds.

Question 12

Uniform

Answer 12

A distribution that doesn’t appear to have any mode and in which all the bars of its histogram are approximately the same height.

Question 13

Symmetric

Answer 13

A distribution when the two halves on either side of the center look approximately like mirror images of each other.

Question 14

Tails

Answer 14

The parts of a distribution that typically trail off on either side.

Question 15

Long Tails

Answer 15

Distributions that straggle off for some distance.

Question 16

Short Tails

Answer 16

Distribution have these if they don’t have data that straggle off for a long distance.

Question 17

Skewed

Answer 17

A distribution is skewed if it’s not symmetric and one tail stretches out farther than the other.

Question 18

Skewed Left

Answer 18

A distribution is this when a longer tail stretches to the left.

Question 19

Skewed Right

Answer 19

A distribution when a longer tail stretches to the right.

Question 20

Outliers

Answer 20

Extreme values that don’t appear to belong with the rest of the data.

Question 21

Center

Answer 21

The place in the distribution of a variable that might be used to summarize the entire distribution with a single number such as mean and median.

Question 22

Median

Answer 22

The middle value, with half the data above and half the data below. It is usually paired with IQR.

Question 23

Spread (measures of…)

Answer 23

A numerical summary of how tightly the values are clustered around the center. IQR and standard deviation are some measures of this…

Question 24

Range

Answer 24

The difference between the lowest and highest values in a data set.

Question 25

Quartile

Answer 25

The median and quartiles (Q1 & Q3) divide data into four parts with equal numbers of data values.

Question 26

Q1

Answer 26

The lower quartile (Q1) is the value with a quarter of the data below it.

Question 27

Q3

Answer 27

The upper quartile (Q3) has three quarters of the data below it.

Question 28

Percentile

Answer 28

The ith percentile is the number that falls above i% of the data.

Question 29

IQR

Answer 29

Interquartile Range is the difference between the first and third quartile.
IQR = Q3 - Q1
Usually reported along with the median.

Question 30

5-number Summary

Answer 30

Summary of a distribution reports the minimum value, Q1, the median, Q3, and the maximum value.

Question 31

Boxplot

Answer 31

A boxplot displays the 5-number summary of Q1, median, Q3, and, whiskers that extend to the non-outlying data values.

Question 32

Mean

Answer 32

The sum of all data values divided by the count. It is usually paired with the standard deviation.

Question 33

Resistant

Answer 33

A calculated summary is said to be resistant if outliers have only a small effect on it.

Question 34

Variance

Answer 34

The sum of squared deviations from the mean divided by the count minus 1.

Question 35

What Standard Deviation is.

Answer 35

The square root of the average squared difference between each data value and the mean.