Chapter 10.7, Problem 9IP

a.

To determine

To find: The experimental probability that an adult prefers to pay bill online.

Answer to Problem 9IP

The experimental probability for online mode is $\frac{9}{40}$ .

Explanation of Solution

Given Information: Table containing relevant data.

Calculation:

Total number of responses $=52+15+18+60+45+10=200$

Number of responses for online mode $=45$

Calculating the required probability,

  $\begin{array}{l}P(online)=\frac{\text{Number of responses for online mode}}{\text{Total number of responses}}\\ =\frac{45}{200}\\ =\frac{9}{40}\text{or 22}\text{.5\%}\end{array}$

Thus, the experimental probability for online mode is $\frac{9}{40}$ .

b.

To determine

To find: The number of customers who will pay their bill by check.

Answer to Problem 9IP

Business should expect that $910$ customers will pay their bill by check.

Explanation of Solution

Given Information: Table containing information from a previous survey. Number of total customers is $3500$ .

Calculation:

Total number of responses $=52+15+18+60+45+10=200$

Number of responses for check mode $=52$

Let $n$ customers will pay their bill by check.

Using percentage proportion to calculate the required number,

  $\begin{array}{l}\frac{n}{3500}=\frac{52}{200}\\ \Rightarrow n\times 200=182000(Cross-product)\\ \Rightarrow n=910\end{array}$

Thus, business should expect that $910$ customers will pay their bill by check.