Statistics Chapter 2.1 Flashcards

Questions and Answers

What is a frequency distribution?

A table showing classes of data entries with counts (correct)

A graph that represents the maximum value of a data set

A measure of statistical variance

A type of data limit analysis

What is the lower class limit?

smallest number in each given class

What is the upper class limit?

largest number in each given class

What does class width refer to?

difference between consecutive lower limits or consecutive upper limits Signup and view all the answers

How is range defined?

maximum minus minimum data entries Signup and view all the answers

What are the steps to construct a frequency distribution from a data set?

Decide on the number of classes, find the class width, find class limits, determine frequency for each class Signup and view all the answers

What is the midpoint of a class?

(upper class limit + lower class limit) / 2 Signup and view all the answers

What does relative frequency measure?

portion or percentage of the data that falls into the class Signup and view all the answers

How is cumulative frequency defined?

sum of the frequency for that class and all previous classes Signup and view all the answers

What is a frequency histogram?

a bar graph representing the frequency distribution of a data set Signup and view all the answers

What does the horizontal scale on a frequency histogram represent?

quantitative and measurable data values Signup and view all the answers

What does the vertical scale on a frequency histogram measure?

frequencies of the classes Signup and view all the answers

What are class boundaries?

numbers that separate classes without forming gaps Signup and view all the answers

What is an ogive?

a graph that displays cumulative frequencies Signup and view all the answers

What is a frequency polygon?

a line graph that emphasizes the continuous change in frequencies Signup and view all the answers

What are the steps to create a frequency polygon?

Choose horizontal and vertical axes, plot midpoint and frequency points, connect the points Signup and view all the answers

What does a relative frequency histogram measure?

relative frequencies of each class on the vertical axis Signup and view all the answers

What is a cumulative frequency graph or ogive?

line graph that displays cumulative frequency of each class at its upper class boundary Signup and view all the answers

Study Notes

Frequency Distributions

A frequency distribution is a table showing classes or intervals of data with counts for each class.
The lower class limit indicates the smallest number in a given class.
The upper class limit specifies the largest number in a given class.

Class and Range Concepts

Class width is calculated by finding the difference between consecutive lower or upper limits, and dividing the range by the number of classes; always round to whole numbers.
Range is determined by subtracting the minimum data entry from the maximum: Range = Maximum - Minimum.

Constructing a Frequency Distribution

Choose the number of classes, typically between 5 to 20.
Calculate class width and establish class limits.
For class limits: the first lower limit is the minimum value; subsequent lower limits are calculated by adding the class width to the previous lower limit. The upper limit is one unit less than the next class's lower limit.
Determine frequencies for each class.

Midpoints and Frequencies

Midpoint of a class is computed as the average of the lower and upper limits: Midpoint = (Lower + Upper) / 2.
Relative frequency represents the proportion of data falling into a class: Relative Frequency = Class Frequency / Sample Size.

Cumulative Frequency

Cumulative frequency is the total frequency for a class and all previous classes; the final class's cumulative frequency equals the sample size.

Graphical Representations

A frequency histogram is a bar graph depicting frequency distributions, where consecutive bars align in width.
The horizontal scale of a histogram represents quantitative and measurable data values.
The vertical scale measures the frequencies of the classes.
Class boundaries eliminate gaps between classes: lower boundary = Lower Limit - 0.5, upper boundary = Upper Limit + 0.5.

Ogives and Polygons

An ogive is a graph illustrating cumulative frequencies.
A frequency polygon is a line graph showing continuous frequency changes, plotted using midpoints and frequencies.

Constructing a Frequency Polygon

Choose horizontal axes for midpoints and vertical axes for frequencies.
Plot points for midpoints and frequencies, connect these points, and extend as necessary.
Start plotting at the first class midpoint minus class width and end at the last class midpoint plus class width.

Relative Frequency Histogram

A relative frequency histogram plots relative frequencies on the vertical axis.

Cumulative Frequency Graph (Ogive)

An ogive line graph displays cumulative frequencies at upper class boundaries, using upper boundaries on the horizontal axis and cumulative frequencies on the vertical axis, without descending back to the horizontal axis.

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Description

Explore essential concepts from Statistics Chapter 2.1 with these flashcards. Learn about frequency distributions, class limits, and more terminology crucial for understanding data organization. Perfect for studying and reinforcing statistical knowledge.