COMM 104 Lecture Notes - Lecture 2: Descriptive Statistics, Variance, Frequency Distribution
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Using scatter plots to study the relationship between variables. To know what the population looks like, find the shape of its distribution. Picture the distribution graphically by any of the following methods: stem-and-leaf display, frequency distributions, histogram, dot plot. Best for small to moderately sized data distributions. Decide which units will be used for the stems and the leaves. Place the stems in a column with the smallest stem at the top of the column and the largest stem at the bottom. Enter the leaf for each measurement into the row corresponding to the proper stem. If desired, rearrange the leaves so that they are in increasing order from left to right. Stem and leaf plot for usage (minutes) stem unit = 100 leaf unit = 10. A frequency distribution is a list of data classes with the count of values that belong to each class: classify and count , the frequency distribution is a table.
