Question

Find P(more than 1 hour of TV | 6th period class). Round to the nearest thousandth. Be sure to show and explain your work.

Did You Watch More Than One Hour of TV Last Night?

Yes
No
3rd period class
9
5
6th period class
11
6

Answer 1

0.647

Explanation:

The table shows the results of a survey of students in two math classes:

`\textsf{Did You Watch More Than One Hour of TV Last Night?}\\\\\begin{array}c\cline{1-3}&\sf Yes& \sf No\\\cline{1-3}\sf 3rd\;period\;class&9&5\\\cline{1-3}\sf 6th\;period\;class&11&6\\\cline{1-3}\end{array}`

Add a total row and column to the table, and fill in the corresponding totals:

`\begin{array}l\cline{1-4}&\sf Yes& \sf No &\sf Total\\\cline{1-4}\sf 3rd\;period\;class&9&5&14\\\cline{1-4}\sf 6th\;period\;class&11&6&17\\\cline{1-4}\sf Total&20&11&31\\\cline{1-4}\end{array}`

The total number of students in the 6th period class is 17.

The number of students who watched more than 1 hour of TV and who were in the 6th period class is 11.

Therefore, the probability that a student watched more than 1 hour of TV given they were in the 6th period class can be calculated by dividing 11 by 17:

`\begin{aligned}\sf P(more\;than\; 1 \;hour \;of\; TV\; | \;6th \;period\; class) &= (11)/(17)\\\\&=0.647058823...\\\\&=0.647\; \sf (nearest\;thousandth)\end{aligned}`

Therefore, the probability that a student watched more than 1 hour of TV given they were in the 6th period class is 0.647 (rounded to the nearest thousandth).