42 terms

Variables

Characteristic of an individual

Categorical Variable

Places individual into a category

Quantitative Variable

Takes numerical values for which it makes sense to find an average

Frequency Table

Table of counts

Relative Frequency Table

Displays percents

Bar Graph

- Label axes

- Title graph

- Scale axes appropriately

- Each bar should correspond to the appropriate count

- Leave room between bars

- Title graph

- Scale axes appropriately

- Each bar should correspond to the appropriate count

- Leave room between bars

Pie Chart

- Include all the categories that make up the whole

- Counts will be percentages

- Counts will be percentages

Shape

Symmetric, skewed

Measures of Center

Mean, Median

Mean

- Most common measure of center

- Arithmetic average

- Arithmetic average

Median

- Midpoint of a distribution

Spread

Range, IQR

IQR

The middle 50%

IQR Equation

Q3 - Q1

Outlier Equation

Less than Q1 - 1.5IQR

Higher than Q3 + 1.5IQR

Higher than Q3 + 1.5IQR

Dotplot

- Only need to properly label horizontal axis

- Title

- Each dot represents a count of 1

- Works well with a small data set

- Title

- Each dot represents a count of 1

- Works well with a small data set

Stemplot

- Separate each piece of data into a "stem" and a "lead"

- Write the stems vertically in increasing order from top to bottom

- Write the leaves in increasing order out from the stem

- Be very neat and leave the same amount of space between leaves

- Title the graph

- Include a key identifying what the stem and leaves represent

- Works well with a small data set

- Write the stems vertically in increasing order from top to bottom

- Write the leaves in increasing order out from the stem

- Be very neat and leave the same amount of space between leaves

- Title the graph

- Include a key identifying what the stem and leaves represent

- Works well with a small data set

Histogram

- Most common graph of a quantitative variable

- The x-axis is continuous, no gaps between bars

- Title the graph

- Divide the range of data into classes of equal width

- Label and scale the axes

- The x-axis is continuous, no gaps between bars

- Title the graph

- Divide the range of data into classes of equal width

- Label and scale the axes

Five-Number Summary

Minimum, Q1, Median, Q3, Maximum

Boxplot

- Drawn from Q1 to Q3

- Line in the middle marks the median

- Lines extend from the box to the smallest and largest observations that aren't outliers

- Line in the middle marks the median

- Lines extend from the box to the smallest and largest observations that aren't outliers

Standard Deviation

- Find the distance of each observation from the mean

- Square each of these distances

- Average the distances by dividing their sum by n-1

- Take the square roon

- Square each of these distances

- Average the distances by dividing their sum by n-1

- Take the square roon

Round-off Error

The error from rounding decimals

When describing the overall pattern of a distribution, you must address...

- Center

- Shape

- Spread

- Outliers

- Shape

- Spread

- Outliers

Dotplot

Histogram

Bar Graph

Frequency Table

Relative Frequency Table

Symmetric

Skewed Right

Skewed Left

Pie Chart

Segmented Bar Graph

Two-Way Table

Back-to-Back Stemplot

Boxplot

Is the mean sensitive to outliers?

The mean is sensitive to outliers.

If a distribution is skewed, use this measure of center

Median

Is the median sensitive to outliers?

The median is not sensitive to outliers.

If a distribution is exactly symmetric, the median and mean will be

Exactly the same

If the distribution is skewed left, the mean will

Fall to the left

If the distribution is skewed right, the mean will

Fall to the right