Question 1195595
<font color=black size=3>
n = 200 = sample size
p = 0.83 = probability of success


mu = mean
mu = n*p
mu = 200*0.83
mu = 166


sigma^2 = variance
sigma^2 = n*p*(1-p)
sigma^2 = 200*0.83*(1-0.83)
sigma^2 = 28.22


sigma = standard deviation
sigma = sqrt(variance)
sigma = sqrt(28.22)
sigma = 5.312249994 which is approximate


Answers:
Mean = <font color=red>166</font>
Variance = <font color=red>28.22</font>
Standard Deviation = <font color=red>5.312249994</font> (approximate)



For more information, check out the Binomial Probability Distribution.
The reason we have a binomial distribution is because either a person uses email or they don't. Also, any employee is independent of any other.  
</font>