p = Estimate of percentage of respondents answering a question
n = Number of respondents that answered the question
The formula involves three basic steps:
1. The amount of variability in the sample denoted by p
2. The standard degree of precision of a 95% confidence interval
3. The sample size denoted by n
Goal of Analysis
Solving for
Y is the measure of output
Y is a function of a series of Xs, The factors affecting Y are a series of Xs.
Calculating Percentile
1. Put all numbers of the data set in numerical order
2. Multiply k% by the total number of numbers n{if you want to know the 90^{th} percentile and you have 25 numbers in the set, you multiply 0.90 x 25 = 22.5}
3. Take that result and round up to the nearest whole number {23}
4. Count the numbers from left to right {lowest to highest} until you reach the value for from step 3 {Your result would be the 23^{rd} number in the series}