Question

A sample of 168 individuals is selected, and the individuals are classified according to their smoking habits and the smoking habits of their parents. The results are given in the contigency table below.
What is the relative frequency of individuals in the sample who have two parents who do not smoke?

Answer 1

First you need to find the totals of the values in the 2 rows and the 3 columns of the contingency table. Then you divide the total number of individuals who have parents neither of which smoke by 168.

Answer 2

well I did 168 divided by 18 and got 9.33333 because that is the only family who doesnt smoke

Answer 3

I mean 47 my bad hold on

Answer 4

I got 3.57

Answer 5

ok sratch that I got 2.5 because I added 47 and 23

Answer 6

When I added the number of individuals who smoke, but have both parents non-smokers (23 individuals) to the number of individuals who don't smoke and who have both parents non-smokers (47 individuals) I get the following:
23 + 47 = 70
The relative frequency of individuals in the sample who have two parents who do not smoke is then given by:
\[\large \frac{70}{168}= this\ fraction\ needs\ simplifying\]

Answer 7

yeah and I got 5/12

Answer 8

Correct!

Answer 9

wait! @kropot72 there is no option to simply, I need to round my answers to a decimal.

Answer 10

all you need to do is put 5/12 into a calculator, and it'll give you 5/12 in decimal form

Answer 11

What he said. ^^^^^

Answer 12

@atlantaslast How many decimal places are required in the answer?

Answer 13

two decimals places.

Answer 14

Then you will need to round up in this case.

Answer 15

how would that be? I just guessed and put 4.1 because it said 0.4166666

Answer 16

but it might be 1.6

Answer 17

Not really. ).416666666 rounded to two decimal places is 0.42.

Answer 18

so the answer would be 0.42?

Answer 19

Correct.

Answer 20

Thanks :)

Answer 21

you're welcome :)