Stats unit 2 flashcards

Frequency Table

A table that organizes data into categories (bins) and shows how often each category appears.

Relative Frequency

The proportion of occurrences in each category, calculated as (class frequency / total data size). It is a property of the data set.

Cumulative Frequency

The sum of the frequencies of a given category and all previous categories.

Stemplot (Stem-and-Leaf Plot)

A method to organize data by separating each value into a 'stem' (leading digit) and 'leaf' (trailing digit).

Modified Stemplot

A variation of a stemplot used for categorical data, where stems represent categories and leaves represent frequency markers.

Bar Graph

A graph that represents categorical data with bars. The x-axis shows categories and y-axis shows frequency or relative frequency.

Pareto Graph

A bar graph where categories are ordered from most to least frequent to visualize significant contributors.

Histogram

A graph used for numerical data where bars represent frequency distributions. The bars touch, indicating a continuous data range.

Bins (Classes)

Grouped ranges of numerical data used in histograms and frequency tables, ideally with equal widths.

Range (of Data)

Calculated as the difference between the largest and smallest values in a dataset, useful for determining bin width.

Class Boundaries

The precise limits of histogram bins, ensuring no gaps between categories.

Ordered Stemplot

A stemplot where leaves are arranged in ascending order within each stem.

Cumulative Relative Frequency

The cumulative frequency divided by the total number of observations.

Class Width

The range covered by each bin in a histogram, ideally calculated as (Range / Number of Bins).

Mean

The average of a data set, calculated as the balancing point of a distribution.

Median

The middle value in a dataset when ordered; if even, the average of the two middle values.

Mode

The most frequent value in a dataset.

Skewness

The asymmetry of the distribution; can be right skewed, left skewed, or symmetric.

Variance

A measure of how much values in a dataset differ from the mean.

Standard Deviation

The square root of the variance, representing the average distance from the mean.

Quartiles

Values that divide a dataset into four equal parts; Q1 (25th percentile), Q2 (median), Q3 (75th percentile).

Interquartile Range (IQR)

The difference between the upper and lower quartiles; it measures the middle 50% of the data.

Boxplot (Box-and-Whisker Plot)

A graphical representation of data based on a five-number summary: minimum, Q1, median, Q3, and maximum.