MATH 1P98 Lecture Notes - Lecture 2: Frequency Distribution, Frequency (Statistics), Skewness

• School: Brock University
• Department: Mathematics and Statistics
• Course: MATH 1P98
• Professor: Sandra Yee

Document Summary

Puts the data into classes, counts the number of points in each class, frequency, f. The total is the total number of data points. 5-10 classes is the ideal amount of classes. The numbers in red are class boundaries, they are the numbers in-between the lower class limits and the upper class limits. Class boundaries don"t allow for gaps between the intervals. No data point will fall on the boundary. Class mark (midpoint): the middle value of the class. For the first class it is (50 + 69) 2 = 59. 5. For the second class it is (70 + 89) 2 = 79. 5 etc. Class width: the difference between two consecutive lower class limits. 69 - 50 = 19 (69 is not a lower class limit) Relative frequency = class frequency / sum of all frequency. Percent frequency = class frequency / sum of all frequency x 100% Answer: 2. 5 + 42. 3 + 44. 9 = 89. 7%