PSY 411 Chapter 2 Notes
Bar graph
- A representation of a frequency distribution, where vertical bars are centered above each category along the x-axis and are separated from each other by a space, indicating that the levels of the variable represent distinct, unrelated categories
\ Class Interval Frequency Distribution
- simplifies frequencies further using bins, but at the expense of losing information
\ Frequency
- How often values appear in the data
\ Frequency Distribution
- A table in which all of the scores are listed along with the frequency with which each occurs
\ Frequency Polygon
- A line graph of the frequencies of individual scores
\ Histogram
- A graphical representation of a frequency distribution, in which vertical bars centered above scores on the x-axis touch each other to indicate that the scores on the variable represent related, increasing values
\ Qualitative Variable
- A categorical variable for which each value represents a discrete category
\ Quantitative Variable
- A variable for which the scores represent a change in quantity
\ Descriptive statistics
- Numerical measures that describe a distribution by providing information on the central tendency of the distribution, the width of the distribution, and the shape of the distribution
\ Mean
- arithmetic average of a group of scores
\ Measure of central tendency
- A number intended to characterize an entire distribution focused on “middleness”
\ \ Median
- middle score after scores are arranged from highest to lowest
\ Mode
- the score in a distribution that has the greatest frequency
\ Range
- A measure of variation; the difference between the lowest and the highest scores in a distribution
\ Apparent limit
- Scores: Simplifies frequencies further using bins
Exact/real limit
- the lower or upper value for a continuous variable measured on a ratio scale
- above and below frequencies
\ Relative frequency
- gives you sense of weighting/ how much of total group are we seeing
- - should equal to around 1
\ Relative frequency %
- Turning the relative frequency into percentage
- total should equal 100
\ Midpoint
- Middle value of apparent limit
\ Cumulative frequency
- adding above and below frequency value
\ Cumulative frequency %
- turning the cumulative frequency into percentage
\ Key Concepts
\ What are the benefits of examining and visualizing frequency data?
- Can point to different characteristics of our sample (rare or common responses)
- Help us find errors
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