Chapter 6.2, Problem 50E

To determine

To Calculate: the mean for S and explain it

Answer to Problem 50E

  $\mu =3.1$

Explanation of Solution

Given:

  $\begin{array}{l}{\mu }_X=2.1\\ {\sigma }_X=1.136\\ {\mu }_Y=1.0\\ {\sigma }_Y=1.0\end{array}$

X= number of nonword errors in a randomly selected essay

Y= number of word errors in a randomly selected essay

Calculation:

  $\begin{array}{c}\mu ={\mu }_X+{\mu }_Y\\ =2.1+1.0\\ =3.1\end{array}$

There are two mean of two different random variables ${\mu }_X=2.1$ and ${\mu }_Y=1.0$ so the mean of the two random variable will be the sum of their means. The total number of errors will be on average 3.1 errors.