Of all individual tax returns, 37% comprise errors made by taxpayer. If IRS examiners are assigned randomly chosen returns in batches of 12, find out the mean and standard deviation for number of erroneous returns per batch.
a. µ=2.80, σ=1.67
b. µ =4.44, σ =1.67
c. µ =4.44, σ =2.80
d. µ =2.80, σ =2.10