click below
click below
Normal Size Small Size show me how
Section 2.2-2.3
Frequency Distributions & Histograms_Probability & Statistics - Math 1530
Term | Definition |
---|---|
Frequency Distribution/Table | Shows how a data set is partitioned among all of several categories (or classes) by listing all of the categories along with the number of data value in each of the categories. |
Frequency | The number of original values that fall into that class. |
Lower Class Limits | The smallest numbers that can actually belong to different classes. |
Upper Class Limits | The largest numbers that can actually belong to the different classes. |
Class Boundaries | "Fence posts"; separates classes; Always 1 more class boundary than the number of classes. Find 2nd boundary by averaging the 1st class upper limit with 2nd lower limit. Add class width to get the others. |
Class Midpoints | The values in the middle of the classes & can be found by adding the lower class limit to the upper class limit and dividing the sum by two. |
Class Width | The difference between consecutive lower class limits or two consecutive lower class boundaries. |
Relative Frequency Distribution | Includes the same class limits as a frequency distribution, but the frequency of a class is replaced with a relative frequencies (a proportion) or a percentage frequency (a percent). |
Relative Frequency Histogram | Has the same shape & horizontal scale as a histogram, but the vertical scale is marked with relative frequencies instead of actual frequencies. |
Normal Distribution | "bell" shaped; Frequencies start low, then increase to one or two high frequencies, then decreases to a low frequency. approx symmetric |
Histogram | Class boundaries, class midpoints, lower class limits. Horizontal: use class boundaries or class midpoints. Vertical: use class frequencies. |
Cumulative Frequency Distribution | Example: instead of 60-69 it will list "Less than 70" |