## anonymous one year ago 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?

1. anonymous

2. kropot72

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.

3. anonymous

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

4. anonymous

I mean 47 my bad hold on

5. anonymous

I got 3.57

6. anonymous

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

7. kropot72

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: $\large \frac{70}{168}= this\ fraction\ needs\ simplifying$

8. anonymous

yeah and I got 5/12

9. kropot72

Correct!

10. anonymous

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

11. Vocaloid

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

12. kropot72

What he said. ^^^^^

13. kropot72

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

14. anonymous

two decimals places.

15. kropot72

Then you will need to round up in this case.

16. anonymous

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

17. anonymous

but it might be 1.6

18. kropot72

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

19. anonymous

so the answer would be 0.42?

20. kropot72

Correct.

21. anonymous

Thanks :)

22. kropot72

you're welcome :)