Download presentation
Presentation is loading. Please wait.
Published byVivien Anderson Modified over 5 years ago
1
Chapter 4 Graphing I. Why? Describes data visually, more clearly. Frequency Distribution Class Interval Column – divides the scores up into categories (0-4, 5-9, etc.). Usually range of 2,5,10, or 25 data points. Main thing: be consistent! Frequency Column – number of scores within that range or category. See example: p.50 Graphs Histogram – shows the distribution of scores by class interval. Can compare different distributions on the same histogram. Shows: Variability (p. 59) Skewness (p. 59). If the mean is greater than the median, positive skewness. If median is greater than mean, negative skewness.
2
Example Psychology Test scores (range from 46-167.
3
Central Tendency and Variability
Centre
4
Central Tendency and Variability
Spread
5
Skewness If the data set is symmetric, the mean equals the median.
6
Skewness If the data set is skewed to the right, the mean is greater than the median. Median Mean
7
Skewness If the data set is skewed to the left, the mean is less than the median. Mean Median
8
B. Column Charts – used to compare frequencies of different categories with one another; simply tells the quantity of a category according to some scale. Categories are on the x-axis and values (scores) on the y-axis (p. 63 example). SCALE IS IMPORTANT (CSPAN-drug use story). Bar Charts – same as Column chart, but reverse the axes. Line Chart – Used to show trends (e.g. rise and fall in pres. popularity – line on our website or see example p. 64). Pie Charts – Great for proportions (percent of MS budget going to each budget category, like education). SPSS and Graphing: Exercises in class (Histogram, Bar, Line).
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.