Calculate probaility form a table of data

Hi can someone check over my work?

I have a table of data and i need to calculate the probability of an event

so the chart is like this


...................Total........................B
A..................163.........................5%


so if i wanted to calculate the probability of being A and B i would...

take the total and multiply it by the % of B

163*0.05
= 8.15

then take that number and divide it by the total

8.15/163
=5%

so the probability of being A and B is 5% right?


Thanks

I am not quite sure what you mean. What's the chance of being A?

This one is less confusing

........................total #.......Drinking Classification-Heavy (%)
employed males.......163..................6.1
employed females.....173..................1.2

Thats all the info i have

I want to calculate the prob of being an employed person who is a heavy drinker



thanks

wind said:

........................total #.......Drinking Classification-Heavy (%)
employed males.......163..................6.1
employed females.....173..................1.2

Click to expand...

You may first wish to get unified data.

163*0.061 = 9.943
173*0.012 = 2.076

First, I am massively concerned that these are not integers. I am tempted to round these values to integers. This may cast a shadow or two on the data, but in this case it seems okay since rounding could cause what is observed. In any case, let's just go with the partial people.

Total in study: 163+173 = 336
Total Haevy Drinkers: 9.943+2.076 = 12.019

% Heavy Drinkers: 12.019/336 = 0.0.27708

Now what?

thanks, tkhunny

but i dont know what to do next , is'nt that the answer? thinking about the dice example, say if ur tring to roll a 2, you have to know the total # of ways that the event would occur (1) over the total possibilities (6) so 1/6. Is'nt that what you just did, total # of drinkers/total#of people?
or am i missing something...? :?
Thanks

I believe you are on the right track. It is very important to know when you are done. I finished with a ratio. You will have to express it as a probability and directly address the problem statement. There is always a bit of formality after the arithmetic is done. We call it communication!

Good work. What else have you? Did you provide a formal answer for the first one? I didn't check.

Thanks tkhunny!

I was able to get the first one