Whats a valid percentage?
A percentage that is calculated using only those respondents who actually answered the question. Missing values are not included. So, if you asked 50 people in this class if they had learned anything, and if 42 said yes, and 5 said no, and 3 didn’t answer ore weren’t present, you would calculate a valid percentage of those saying yes as 42/47 x100%. If you used 42/50 x100% you would be including the 3 missing values in your calculation as a no. That would be inaccurate. SPSS, when it gives a valid percentage is not counting the missing values in the sample size or denominator. See Babbie and Halley, p. 38. • What’s a cumulative percentage and when would I want to know? A cumulative percentage adds all the percentages for each category up to that point. See, Babbie and Halley, p.38. Example, the frequency distribution of religious identification on B and H, p.37. 63.1% of the respondents were Protestant. 23.9% were Catholic. If we collapse those categories to Christian, then we can use
