Question

The mean number of $0$s in a line $40$digits long is

(a) $10$

(b) $4$

(c) $3.098$

(d) $0.4$

(e)$0.1$

Short answer

The mean number of $0$s in a line $40$digits long is an option (b) $4$.

Step-by-step solution

Given Information 

Mean or average is defined as the difference between the sum of all the numbers and the total number of numbers; it is, therefore, the average of all of them.

Explanation 

Given:

$p=0.1$

localid="1649675921896" $n=40$

The mean is the product of the sample size $n$and the probability $p:$:

localid="1650043663992" $$\begin{gathered} {\mu }_X=np \\ =40\left(0.1\right) \\ =4 \end{gathered}$$

Hence, the answer is option (b) $4$.