unit 1 stats

Categorical Variables

Variables that take on values as category names or group labels.

Frequency Tables

Tables that show the number of cases falling into each category.

Relative Frequency Tables

Tables that give the proportion or percent of cases falling into each category.

Quantitative Variable

Variable that takes on numerical values for a measured or counted quantity.

Discrete Quantitative Variable

Variable with a finite or countable number of values.

Continuous Quantitative Variable

Variable that can take on uncountable or infinite values with no gaps.

Center

The point that divides the values or area under the curve in half.

Spread

The scope of values from smallest to largest in a distribution.

Variability

The key concept in statistics indicating how values are scattered around the center.

Median

The middle number of a set of numbers arranged in numerical order.

Mean

The average found by summing items in a set and dividing by the number of items.

Range

The difference between the largest and smallest values in a dataset.

Interquartile Range (IQR)

The range of the middle 50% of values in a dataset.

Variance

The average of the squared differences from the mean in a dataset.

Standard Deviation

The square root of the variance, indicating the typical distance of values from the mean.

Spread

The difference between the maximum and minimum values in a distribution, indicating the variability of the data.

Unusual features

Characteristics of a distribution such as outliers or gaps that deviate from the typical pattern.

Shape

The overall form of a distribution, like being symmetric, skewed, or uniform.

Center

The measure that represents the middle of a distribution, like the mean or median.

Median

The middle value in a dataset when arranged in ascending order, dividing the data into two equal halves.

Interquartile range

The range of the middle 50% of data, calculated as the difference between the third and first quartiles.

Normal distribution

A bell-shaped, symmetric distribution where data clusters around the mean following the empirical rule.

Empirical rule

A guideline for normal distributions stating the percentage of data within 1, 2, and 3 standard deviations from the mean.