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# Binomial Distrbution : Mean, Variace and S.D.

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The probability that an individual is left-handed is 0.1. In a class of 30 students, what is the probability of finding at least five left-handers?

Construct a binomial distribution.

Find the mean, variance and standard deviation of the distribution.

https://brainmass.com/statistics/probability/binomial-distrbution-mean-variace-and-s-d-206133

#### Solution Preview

Please refer attached file for better clarity of tables and formulas in MS Excel.

Solution

n = 30
p= 0.1
q = 1-0.1=0.9

It is binomial distribution

Mean = n*p = 30*0.1 =3
Variance = n*p*q = 30*0.1*0.9=2.7
Standard Deviation= sqrt(Variance) =sqrt(2.7)= 1.643168
We can use binomdist function to get probabilities and make binomial distribution

No. of success, r Probability p
0 0.0423911583
1 ...

#### Solution Summary

Solution describes the steps for calculating mean, variance and standard deviation for binomial distribution. It also explains building binomial distribution.

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