The Number of Bad Checks Received Per Day by a Store

Short Answer

The number of bad checks received per day by a store and the respective probabilities are shown below.
$\begin{array}{ll}\text { Number of Bad Checks }\\\text { Received Per Day }&\text { Probability }\\0 & 0.04 \\1 & 0.06 \\2 & 0.10 \\3 & 0.30 \\4 & 0.20 \\5 & 0.15 \\6 & 0.10 \\7 & 0.05\end{array}$
a. What is the expected number of bad checks received per day?
b. Determine the variance in the number of bad checks received per day.
c. What is the standard deviation?