UNIT 1 | Exploring One Variable Data

Statistic

Any information learned from a piece of sample data.

Parameter

Any information learned from a population.

Variables

Characteristics that can change from individual to individual.

Categorical Variable

Takes on values that are category names or group labels.

Quantitative Variable

Takes on numerical values that are measured or counted.

Frequency

The number of each category in a sample.

Relative Frequency

The proportion of each category in a sample.

Distribution of Data

Values the data takes on and how often.

Discrete Data

Takes on a countable number of finite values.

Continuous Data

Takes on infinitely many values that cannot be counted.

Dot Plot

A type of graph for quantitative data.

Stem and Leaf Plot

A type of graph for quantitative data.

Histogram

A type of graph for quantitative data.

Cumulative Graph

A type of graph for quantitative data.

Measures of Center

Mean and Median.

Mean

Sum of data values divided by the number of values.

Median

The middle value of a dataset.

Measures of Position

Percentile, Quartiles.

Percentile

Value containing p% of data less than or equal to it.

Interquartile Range (IQR)

Q3 - Q1, spread of the middle 50% of data.

Standard Deviation

Measure of variability from the mean.

Outliers

Unusual features in the data.

Five Number Summary

Min, Q1, Median, Q3, Max.

Box Plot

Graphical representation of the five number summary.

Z-Score

Measure of how many standard deviations above or below the mean.