Originally Posted by Blackhatbrigade
Also, how did we come to the conclusion of:
Quote
Originally Posted by Priapologist
8.352 inches: 1 in 741
9.177 inches: 1 in 31, 574
10.00 inches: 1 in 3.5 million
From a group of 300 people? `:-)
Or is that what the talk of distribution is? That stuff kinda lost me.
The 300 men in the Ansell LifeStyles condom survey act as a representative sample of the whole male population. The sample size is large enough to do such basic statistics on and those data are backed up by every other clinician-measured survey that I have seen. In fact, the Ansell’s study is actually on the high side of the reported numbers, so my statistical analysis is probably over estimating the average penis size and distribution.
The basic idea behind this process: say that I have a jar containing 10,000 marbles of various colors and I want to know more or less how many of each color I have. I can either count all 10,000, which would be tedious, or I can pull out 50 marbles at random and note the colors obtained and their frequency. This is a sample (50) of a population (10,000). So Ansell pseudo-randomly* noted the erect lengths and girths (analogous to marble color), and how often those data occurred (frequency), of 300 American university students on holiday in Cancun.
Penis sizes, like most natural phenomena, adopt a normal or near-normal distribution, wherein 68% of the sample (and hence the population from which the sample is drawn) will fall within one standard deviation from the mean, or average, value. Likewise, 96% of the sample will fall within two standard deviations, and 99.6% will fall within three standard deviations (SD). Hence, 8.352 inches is three SD from the mean, 9.177 inches is four SD, et cetera. A z-score calculator determines the odds, 1 in x.
That is how 300 drunken frat boys informs the rest of us how long the average penis is.
*I said pseudo-random here because this is a biased sample, both from the design criteria and due to self-selection bias, i.e. guys with bigger penises were probably more willing to get measured than guys with shorter/thinner penises… which further suggests that this analysis is on the high side of the ‘true’ averages.
Pri