# Variance and the Standard Deviation

In San Francisco, 30% of workers take public transportation daily.

a) In a sample of 10 workers, what is the probability that exactly three workers take the public transport daily? [Hint: It is a Binomial Distribution Problem.]

f(3) =

b) In a sample of 10 workers, what is the probability that at least three workers take the public transport daily?

P(x?3)=1-f(0)- f(1)- f(2)

f(0) =

f(1) =

f(2) =

P(x?3)=1-f(0)- f(1)- f(2) =

c) How many workers are expected to take the public transportation daily?

E(X) =

d) Compute the variance and the standard deviation of the number of workers that will take the public transport daily.

Var(X) =

Standard Deviation =

https://brainmass.com/statistics/binomial/variance-and-the-standard-deviation-506209

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