Visual Display of Data 1: Frequency Distribution

Flashcards covering key vocabulary and concepts related to frequency distribution, bar charts, histograms, and scatter plots from the lecture notes.

Frequency Distribution

A way of organizing data to see how often each value (or group of values) occurs, grouping data into categories or intervals, and recording the number of times each category appears (its frequency).

Tabular Form

A type of frequency distribution that displays data in a table with categories (or intervals) and their corresponding frequencies.

Graphical Form

A method of showing frequencies using visuals, commonly including bar charts, histograms, and scatter plots.

Bar Chart

A graphical display of a frequency distribution using rectangular bars of equal width, where the height (or length) represents the frequency of a category or group. It is best suited for categorical data, and bars are separated by gaps.

Histogram

A graphical display of a frequency distribution for numerical data, grouping numbers into adjacent intervals (bins or classes) to show the continuous nature of the data, with no gaps between bars.

Number of Classes (Histogram)

The number of bins in a histogram, typically chosen as 10-20 for large datasets or 4-6 for small ones, following the thumb rule: (number of observations / desired class size, at least 4).

Class Width (Histogram)

The size of each interval in a histogram, calculated as (Range of data / Number of classes) and always rounded up to a convenient number.

Lower Limits (Histogram)

The starting values for each class interval in a histogram, generated by adding multiples of the class width to the smallest data value or a convenient smaller value.

Upper Class Limits (Histogram)

The ending values for each class interval in a histogram, calculated by adding the class width to each lower limit and then subtracting the smallest significant unit in the data (e.g., 1 for whole numbers) to avoid interval overlap.

Class Boundaries (Histogram)

The precise points that separate adjacent classes in a histogram, typically defined as the midpoint between the upper limit of one class and the lower limit of the next (e.g., using a ±0.5 rule).

Scatter Plot

A graph that shows the relationship between two variables, where each data point is displayed as a dot on a coordinate plane, with one variable on the x-axis and the other on the y-axis.

Positive Relationship (Scatter Plot)

A pattern in a scatter plot where as one variable increases, the other variable also tends to increase.

Negative Relationship (Scatter Plot)

A pattern in a scatter plot where as one variable increases, the other variable tends to decrease.

No Clear Relationship (Scatter Plot)

A pattern in a scatter plot where points are scattered randomly, indicating no apparent connection or trend between the two variables.

Outliers (Scatter Plot)

Data points in a scatter plot that are significantly distant (far away) from the rest of the points, indicating unusual or anomalous values.