Chapter 8 Making Sense Of The Numbers

Question 1

Units

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Answer 1

The precise meaning of the numbers in quantitative variables - how many of what the numbers refer to. (units of measurement)

Question 2

Rate

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Answer 2

Share of a population with a particular characteristic, which is expressed relative to some base size population.
Rate = (Count/Population) x Base

Question 3

Risk

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Answer 3

Share of a population with a particular condition or disease, which is expressed relative to some base size population.

Question 4

Percent change
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Answer 4

Change relative to the starting base, expressed as percentage.

Question 5

Percentage point change

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Answer 5

The change of a variable measured in its own units when it is a percent-age.

Question 6

Rate of change

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Answer 6

How rapidly a variable changes.

Question 7

Odds

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Answer 7

For an outcome that has only two possibilities, the ratio of one outcome (e.g. success) to the other possible outcome (e.g. failure).

Question 8

Prevalence

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Answer 8

The number or share of the population that has a particular disease or condition.

Question 9

Incidence

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Answer 9

The rate at which new cases of a disease or condition appear in a population.

Question 10

Distribution

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Answer 10

The pattern of values spread out over a variable’s categories or numerical range, illustrating which values are taken on and how often.

Question 11

Frequency distribution

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Answer 11

The distribution of a categorical variable showing the count or percentage in each category.

Question 12

Bar chart
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Answer 12

A graph for displaying categorical data with bars representing each category.

Question 13

Pie chart
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Answer 13

A graph showing percentage among categories, shown as segments of a circle.

Question 14

Histogram

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Answer 14

A graph showing the distribution of a quantitative variable.

Question 15

Mean

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Answer 15

Average of a quantitative variable - the sum of all observations divided by the number of observations.

Question 16

Outliers

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Answer 16

Extreme scores or observations that stand out in a distribution.

Question 17

Skewness

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Answer 17

Characteristic of a distribution that is not symmetrical and has one tail longer than the other.

Question 18

Median

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Answer 18

The value at the point that splits the distribution into two halves, the 50th percentile in the distribution of a quantitative variable.

Question 19

Standard deviation

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Answer 19

Common measure of variability of a quantitative variable.

Question 20

Variance

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Answer 20

A measure of spread of a quantitative variable, the square of the standard deviation.

Question 21

Z (standardized) scores

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Answer 21

A variable converted to standard deviation units and shifted to mean zero.

Question 22

Quantile

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Answer 22

Points taken at regular intervals (such as every quarter or tenth) in a distribution.

Question 23

Coefficient of variation (COV)

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Answer 23

A measure of spread equal to the standard deviation divided by the mean.

Question 24

Cross-tabulation

p.256

Answer 24

Method to describe the relationship between two categorical variables, either ordinal or nominal.

Question 25

Relative risk | p.259

Answer 25

Ratio of the risk of two groups.

Question 26

``` Odds ratio (OR) (p.259) ```

Answer 26

Ratio of the odds of an outcome for one group to the odds of the outcome for another group.

Question 27

Scatterplot | p.260

Answer 27

A graph illustrating the values two quantitative variables take on in data.

Question 28

Correlation | p.261

Answer 28

A measure of the strength and direction of a relationship between two variables.

Question 29

``` Correlation coefficient (Pearson r) (p.261) ```

Answer 29

The expected standard deviation change in one variable if the other variable changes by 1 standard deviation. It is the most common measure of correlation.

Question 30

Outliers | p.251

Answer 30

Extreme scores or observations that stand out in a distribution.

Question 31

Skewness | p.251

Answer 31

Characteristic of a distribution that is not symmetrical and has one tail longer than the other.

Question 32

Median | p.251

Answer 32

The value at the point that splits the distribution into two halves, the 50th percentile in the distribution of a quantitative variable.

Question 33

Standard deviation | p.253

Answer 33

Common measure of variability of a quantitative variable.

Question 34

Variance | p.253

Answer 34

A measure of spread of a quantitative variable, the square of the standard deviation.

Question 35

Z (standardized) scores | p.254

Answer 35

A variable converted to standard deviation units and shifted to mean zero.

Question 36

Quantile | p.255

Answer 36

Points taken at regular intervals (such as every quarter or tenth) in a distribution.

Question 37

Coefficient of variation (COV) | p.255

Answer 37

A measure of spread equal to the standard deviation divided by the mean.

Question 38

Cross-tabulation | p.256

Answer 38

Method to describe the relationship between two categorical variables, either ordinal or nominal.

Question 39

Relative risk | p.259

Answer 39

Ratio of the risk of two groups.

Question 40

``` Odds ratio (OR) (p.259) ```

Answer 40

Ratio of the odds of an outcome for one group to the odds of the outcome for another group.

Question 41

Scatterplot | p.260

Answer 41

A graph illustrating the values two quantitative variables take on in data.

Question 42

Correlation | p.261

Answer 42

A measure of the strength and direction of a relationship between two variables.

Question 43

``` Correlation coefficient (Pearson r) (p.261) ```

Answer 43

The expected standard deviation change in one variable if the other variable changes by 1 standard deviation. It is the most common measure of correlation.