Question

1/ determine where the following statement is true the probability that event a will occur is P(A)= number of succesful outcomes/ number of unsuccessful outcomes

true or false

2/ one hundred people were asked " do you favor stronger laws on gun control?" Of the 33 that answered "yes" to the question, 14 were male . Of the 67 that answered "no" to the question , six were male . If one person is selected at random, what is the probability that this person answered "yes" or was a male? Round to nearest hundredth.

0.53 or 0.67 or 0.13 or 0.39

3/ numbered disks are placed in a box and one box is selected at random. There are 6 red disks numbered 1 through 6 and 7 yellow disks numbered 7 through 13. In an experiment a disk is selected , the number and color noted replaced, and then a second disk is selected is this an example of independence? Yes or no

4/ a single 6 sided die is rolled twice. Find the probability of getting a 2 the first time and 1 the second time. Express the probability as a simplified fraction

A: 1/36. B: 1/12. C : 1/6. D: 1/3

Answer 1

Solution:

1)

Given: P(A)= number of successful outcomes/ number of unsuccessful outcomes

This statement is False, since denominator is the total outcomes in sample space

That is: N = number of successful outcomes + number of unsuccessful outcomes

Thus probability that event a will occur is

P(A) = number of successful outcomes/ N

2)

Given:

one hundred people were asked " do you favor stronger laws on gun control?"

Of the 33 that answered "yes" to the question, 14 were male .

Of the 67 that answered "no" to the question , six were male .

Thus we get:

	Male	Female	Total
Yes	14	19	33
No	6	61	67
Total	20	80	100

Thus the probability that this person answered "yes" or was a male is:

P(Yes or Male) = P(Yes ) + P(Male) - P(Yes and Male)

P(Yes or Male) = 33 / 100 + 20 / 100 - 14 / 100

P(Yes or Male) = 0.33 + 0.20 - 0.14

P(Yes or Male) = 0.39

Thus correct answer is: 0.39

3) . There are 6 red disks numbered 1 through 6 and 7 yellow disks numbered 7 through 13.

In an experiment a disk is selected , the number and color noted replaced, and then a second disk is selected is this an example of independence?

Since we are selecting first disk and after noting down disk is replaced back , so selection first disk does not affect on selection of second disk.

Thus, Yes, this is an example of independence.

4) a single 6 sided die is rolled twice.

Find the probability of getting a 2 the first time and 1 the second time.

That is we have to find the P( getting (2,1) ) = ........?

From above sample space , we can see:

N = total outcomes = 36

and Number of outcomes of event of getting 2 on first and 1 on second die = 1 outcome

Thus

P(getting (2,1) ) =1 / 36