# maths lesson

Discussion in 'The Healthy Penis' started by contortionist, Jul 25, 2008.

1. ### contortionist New Member

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In the UK there are about 60million people, about half of whom are male and, of those old enough to get an erection, they have dicks varying in length from, say 4'' to 10''.
A normal distribution curve shows that 0.5% should have penis lengths of about 10''. So far so good.
So, about 30m. are male of whom about 70% are boys and men having full erections. ie 21million.
or 21x0.5=0.105m

By this reckoning there are about 100,000 boys and men with dicks over 10'' out there.
Further (spurious) maths says that 30% are between 13 and 16, so 30,000 young boys must have woken up one morning with quite a surprise.

More mental arithmetic concerning amount of ejaculate and distance spurted is available although the data is even more debatable!

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2. ### Joseph VerifiedGold Member

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60m makes 30m?
that' 50%
0.5% is 300 000 from 60m

that's 100 times less

so it's not 30,000 , but 300.... I guess

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Guess again

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4. ### sykray Active Member

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What are your mean and standard deviation for the normal distribution curve of erection lengths? From medically scientific research papers not self reported measurements, the mean is variously 5.1 to 5.3 inches and SD between 0.8 and 0.96.

A 10 inch penis (or more) is about 5 SDs above the mean. This is not 0.5% of the NDC. The % between minus 5SD and plus 5 SD is 99.9999426697. So, above plus 5 SD is half of the remainder = 2.867 x 10 to minus 5.
Apply this to 21 million = 602 guys.

0.5% is 1 in 200. Divide 21,000,000 by 200= 105,000.

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5. ### Golfbuddy Active Member

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This is all speculative of course. There is, and has never been, a definitive study of penis size. In virtually all studies, the measurements were taken from volunteers, and therefore not random in any way, making all statistical calculations spurious and wrong.

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6. ### sykray Active Member

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You are correct in saying that we must be cautious about sampling bias in research. However, the studies I mentioned are much more relaible than self-measured, self-reported surveys.
I was merely trying to re-calibrate contortionist's estimate of 100,000 to the much more realistic 600.
I might add that where men are volunteering to be measured or agreeing to be measured then I would expect the mean to be higher since guys with smaller erections are more likely to refuse.

Here are the 3 studies I referred to:
Schonfeld and Beebe, published in the USA in 1942, found the median length for the group of 20-25 year olds was 13.02 cm. or 5.12 in. This is extremely close to the 12.89 cm. or 5.07 in. erect penis average produced a careful modern study (Wessells, Lue, & McAninch, 1996) in which doctors actually measured the erections of 80 grown men. AND, in the recent Italian study of 3,300 soldiers age 17-19, Ponchietti and his colleagues found the average stretched penis length (remember this is very close in length to the erect penis) to be 12.5 cm. or 4.92 in.
Penile length and circumference: a study on 3,300 young Italian males.

Ponchietti R, Mondaini N, Bonafe M, Di Loro F, Biscioni S, Masieri L.

Department of Urology, University of Florence, Italy.

OBJECTIVE: The knowledge of normal variations in the size of male external genitalia is of considerable interest to several disciplines. We carried out an extensive study in young Italian males to provide estimates of normal variations of penile dimensions. METHODS: The penile length in flaccid and stretched states and the penile circumference were measured in a random group of 3,300 young men aged 17-19 years and free from endocrine disorders and from congenital or acquired abnormalities of the penis. In a random sample of 325 subjects of the same set of people, penile length and circumference were also correlated with weight and height. Statistical analysis was performed with the Spearman test, because our data were not normally distributed as tested by the Kolmogorov-Smirnov test (p < 0.01). RESULTS: The median values of penile dimensions recorded in the present study are flaccid length 9.0 cm, flaccid circumference, at the middle of the shaft, 10.0 cm, and stretched length 12.5 cm. [4.92 inches] We also observed that the penile dimensions are highly correlated with height and weight. CONCLUSIONS: Since penile length and circumference correlate with anthropometric parameters such as weight and height, we suggest to consider themselves as two bodily measures which display a wide extent of normal variability along the general population.

Penile length in the flaccid and erect states: guidelines for penile augmentation.

Wessells H, Lue TF, McAninch JW.

Department of Urology, University of California School of Medicine, San Francisco, USA.

PURPOSE: We provide guidelines of penile length and circumference to assist in counselling patients considering penile augmentation. MATERIALS AND METHODS: We prospectively measured flaccid and erect penile dimensions in 80 physically normal men before and after pharmacological erection. RESULTS: Mean flaccid length was 8.8 cm., stretched length 12.4 cm. [4.88 inches] and erect length 12.9 cm. [5.08 inches] Neither patient age nor size of the flaccid penis accurately predicted erectile length. Stretched length most closely correlated with erect length. CONCLUSIONS: Only men with a flaccid length of less than 4 cm., or a stretched or erect length of less than 7.5 cm. should be considered candidates for penile lengthening.

There is not a great deal of point in trying to give averages for each teenage year as guys are at different stages of puberty. The variation from shortest to longest is too wide to make an average length a logical measure.

We can say though, from the three studies above where a doctor measured the penis and not self- report surveys, that the average erection length is 5.1 inches (14cms) and roughly two-thirds of men will have erections between 4 and 6.2 inches (10 and 15.7cms). 16% will have erections smaller than 4 inches. 97.5% of men will have erections less than 7.3 inches (18.5cms). Therefore five men in 200 will have erections of 7.3 inches or more. One man in a thousand will have an erection of 8.4 inches (22cms) or longer and one man in 10,000 will have an erection of 9 inches or longer (22.9cms). For every million men in the population there will be a hundred erect penises of 9 inches or more.

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Last edited: Jul 28, 2008
7. ### contortionist New Member

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In other words there are LIKELY to be hundreds of guys walking around with 9 or 10 inch dicks hanging between their legs. I didn't mean this to be an exact science just a bit of fun although I appreciate the efforts made by fellow number crunchers.
Although the SD of penis length appears to be an accurate construct, it doesn't account for the myriad of measuring techniques. For example, I'm resting a 12''ruler along the surface of my penis and it's showing 6.5''erect. If I now hold the ruler and push it onto the pubic bone it grows by an inch; - 1.5'' if I push hard. Surely 'degrees' of pushing shouldn't count and measurements should only be made by RESTING the ruler on the surface?
And the reason for this topic? Apart from the fun of maths, I did know a guy who, at the age of 13 grew a ten inch dick. I would like to think he's not alone.

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8. ### D_Crystallized Ginger New Member

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are you a math or stats teacher? btw your calculations sounds good to me and more realistic too!

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