# need help with this staticstics question (point me in right dirrection please)

• Sep 10th 2011, 07:09 AM
nitros
need help with this staticstics question (point me in right dirrection please)
Hello, sort of left an assignment to the last minute and am in desperate need of help
The results are in for the paper toss game and we have found that each participant's accuracy
(closeness to the coin) is dependent on the weight of the paper used as a ball. To show the
distinction, we have constructed the following contingency table from 200 samples:
Wc W
D 84 22
Dc 36 58
where W is the weight of the paper is less than 80 gsm, and D is the distance recorded is less
than or equal to 20 cm from a paper toss.
Note: you are allowed to use the text book probability tables when answering these questions.
When a table lookup has been performed, make it obvious by writing `from Table x', where x is
replaced by the table number used or the page number.
1 Probabilities
From the above contingency table, compute:
1. the probability that the distance is less than or equal to 20 cm and the weight is greater
than or equal to 80 gsm.
2. the probability that the distance is greater than 20 cm and the weight is greater than or
equal to 80 gsm.
3. the probability that the distance is less than or equal to 20 cm given that the weight is
greater than or equal to 80 gsm.
4. the probability that the distance is less than or equal to 20 cm given that the weight is less
that 80 gsm.
i dont get the whole table part, i know c = the event that it doesnt occur so am i suppose to put like probability 22 that both occur ? or is there an equation that i need to do? help will be greatly appreciated thanks.
• Sep 10th 2011, 02:30 PM
mr fantastic
Re: need help with this staticstics question (point me in right dirrection please)
Quote:

Originally Posted by nitros
Hello, sort of left an assignment to the last minute and am in desperate need of help
The results are in for the paper toss game and we have found that each participant's accuracy
(closeness to the coin) is dependent on the weight of the paper used as a ball. To show the
distinction, we have constructed the following contingency table from 200 samples:
Wc W
D 84 22
Dc 36 58
where W is the weight of the paper is less than 80 gsm, and D is the distance recorded is less
than or equal to 20 cm from a paper toss.
Note: you are allowed to use the text book probability tables when answering these questions.
When a table lookup has been performed, make it obvious by writing `from Table x', where x is
replaced by the table number used or the page number.
1 Probabilities
From the above contingency table, compute:
1. the probability that the distance is less than or equal to 20 cm and the weight is greater
than or equal to 80 gsm.
2. the probability that the distance is greater than 20 cm and the weight is greater than or
equal to 80 gsm.
3. the probability that the distance is less than or equal to 20 cm given that the weight is
greater than or equal to 80 gsm.
4. the probability that the distance is less than or equal to 20 cm given that the weight is less
that 80 gsm.
i dont get the whole table part, i know c = the event that it doesnt occur so am i suppose to put like probability 22 that both occur ? or is there an equation that i need to do? help will be greatly appreciated thanks.