Chapter 2- Exploring Data: Frequency Distributions and Graphs Flashcards Preview

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Flashcards in Chapter 2- Exploring Data: Frequency Distributions and Graphs Deck (19):

Simple frequency distribution

Scores arranged from highest to lowest, with the frequency shown for each score

Tells you where the majority of the data lie. Don't care about individual people, care about most

Pick up valuable info with just a glance, can easily see measures of central tendency


Raw scores/data

Score obtained by observation/experiment


How to make a simple frequency graph

1. Make labels/titles- variable, tally, frequency, cumulative frequency, graph title

2. Write all numbers from highest to lowest

3. Put tally scores in that column (tallies only used for rough drafts)

4. Put amount of tallies in frequency box

5. By the end of cum. Frequency it says N


Grouped frequency distributions

When your data is all over the place, use grouped to simplify it down

These are scores compiled into equal sized Intervals, includes the frequency of score in each interval

Should be 10-20 groups


Frequency distributions are what kind of statistics?

Descriptive statistics. Because it describes a particular characteristic of data
Show us where the majority of the data lie, a characteristic


Quantitative graphics?

Frequency polygon or histogram


Frequency polygon

A frequency distribution graph used to graph quantitative variables

The frequency points are connected by lines

Each point represents two numbers: the class midpoint directly below it on the X axis and the frequency of the class directly across from it on the Y axis

Name of the variable being graphed goes on the x axis


How to make a frequency polygon

Variable name on x axis
X- variable

Dots are midpoint of the intervals



Quantitative graphing technique

Made by raising X bars to the appropriate frequencies


When to use frequency polygon v histogram?

If you are displaying two overlapping distributions on the same axes, a frequency polygon is less cluttered than a histogram

But on a histogram- it is easier to read frequencies, and are a better choice when presenting discrete data


Qualitrative data?

Bar graph


Bar graph

Represents qualitative variable

Looks like a histogram but has wider space between bars

Use with an ordinal or nominal scale


Symmetrical distributions

Have two halves that more or less mirror each other


2 types of symmetrical distribution

Normal distribution
Rectangular distribution


Normal distribution

Bell shaped distribution


Rectangular distribution

Literally looks like a rectangle, occurs when the frequency of each value on the x axis is the same


Skewed distributions

Scores that most frequently are near one end of the scale, leaving few scores on the other


Positively skewed

Thin point to the right
Mode, median, average


Negatively skewed

Thin point to the left
Average, median, mode