Relative Frequency 2/11/16
Relative Frequency Practice Problems
http://www.mathopolis.com/questions/quiz.php
Continuous Variable
Some variables (such as time, height and weight) are not limited to a fixed set of indivisible categories. These variables are called continuous variables, and they are divisible into an infinite number of possible values. For example, time can be measured in fractional parts of hours, minutes, seconds and milliseconds. So, instead of finishing a race in 11 or 12 minutes, a jockey and his horse can cross the finish line at 11 minutes and 43 seconds.
relative frequency
The fraction or proportion of times an answer occurs. How often something happens divided by all outcomes. Example: Your team has won 9 games from a total of 12 games played: the Frequency of winning is 9. the Relative Frequency of winning is 9/12 = 75%
Frequency
The number of times a given datum occurs in a data set
Cumulative Frequency
The total of a frequency and all frequencies so far in a frequency distribution. It is the 'running total' of frequencies. https://www.mathsisfun.com/definitions/cumulative-frequency.html
Cumulative Frequency: Discrete v. Continuous
http://www.statcan.gc.ca/edu/power-pouvoir/ch10/5214862-eng.htm
Sampling and Data: Frequency, Relative Frequency, and Cumulative Frequency practice problems
https://cnx.org/contents/jsYjzeoo@20/Sampling-and-Data-Frequency-Re
cumulative relative frequency
relative frequency of all data less than or equal to a particular value How to make a cumulative relative frequency distribution: https://www.youtube.com/watch?v=kBX9aNdOYDg
Discrete Variable
Consists of separate, indivisible categories. No values can exist between a variable and its neighbor. For example, if you were to observe a class attendance registered from day-to-day, you may discover that the class has 29 students on one day and 30 students on another. However, it is impossible for student attendance to be between 29 and 30. (There is simply no room to observe any values between these two values, as there is no way of having 29 and a half students.)
Frequency Table Example
Create a frequency table. List the possible outcomes of your data in a vertical column. To the right, make a second column that lists the frequencies. Suppose you roll a single die 20 times and get the following rolls: [5, 4, 4, 2, 6, 4, 1, 5, 4, 1, 6, 2, 2, 1, 2, 2, 4, 1, 2, 2]. The left column would read from top to bottom: 1, 2, 3, 4, 5, 6. The second column would read from top to bottom: 4, 7, 0, 5, 2, 2. Add a relative frequency column to make a relative frequency table. In a third column, write the frequency divided by the total number outcomes. There are 20 outcomes. The numbers in the third column, the relative frequency column, will be in order from top to bottom: 4/20 = 0.2, 7/20 = 0.35, 0/20 = 0, 5/20 = 0.25, 2/20 = 0.1, 2/20 = 0.1. You can also think of these decimals as percents. For instance, 25 percent of the rolls came up with five. Add a cumulative relative frequency column to the table. Each row in the column is the sum of all the relative frequencies up to and including that line. From top to bottom, the third column will read 0.2, 0.2 + 0.35 = 0.55, 0.2 + 0.35 + 0 = 0.55, 0.2 + 0.35 + 0 + 0.25 = 0.8, 0.2 + 0.35 + 0 + 0.25 + 0.1 = 0.9 and 0.2 + 0.35 + 0 + 0.25 + 0.1 + 0.1= 1. You can also think of these decimals as percents. You will now have a table with three columns and six rows. Analyze the meaning of the table. The table says that 20 percent of the rolls were one or less, 55 percent were two or less, 50 percent were three or less, 80 percent were four or less, 90 percent were five or less and 100 percent were six or less.
