1. In a basket there are 6 red marbles

and 4 blue marbles.

What is the probability of drawing

a red marble--P(R)?

2. In a basket there are 6 red marbles

and 4 blue marbles.

Given that you have selected a red marble and have placed

it in the basket, what is the probability of drawing a red

marble---P(R) ?

3. In a basket there are 6 red marbles

and 4 blue marbles.

However, what is the probability of selecting a red marble,

assuming that you did not replace the original red marble, i.e.,

sampling without replacement.

4. In a basket there are 6 red marbles

and 4 blue marbles.

What is the probability of drawing a red marble on the first try

and without replacing it, drawing a blue marble on the second try?

P (B|R)=

5. In a basket there are 6 red marbles

and 4 blue marbles.

What is the probability of drawing a red marble on the first try,

a blue marble on the second try, and another blue marble on the

third try without replacement?

6. In a basket there are 6 red marbles

and 4 blue marbles.

What is the probability of drawing a red marble on the first try,

a blue marble on the second try, and another blue marble on the

third try "with" replacement?

7. Observe each of the following, assuming independent events.

Given P(A) = 30%, P(B) = 20%,

find P(A and B) =

8. In a certain laboratory we find the following chemicals:

C only 300

H only 500

Both 200

Total 1000

P(C) =

P(H)=

P(B)=

Now find P(C or H)=

P(C only or H only) =

9. If P(A and B and C) = 25% and P(B and C) = 75%

Find P(A)=

10. If P(A|B) = 20% and P(B) = 80%, find P(A and B) =

11. Assume that P(B|A) = 50% ; P(B|A' ) = 10% ; P(A)= 32%:

P(A and B)=

P(A ' and B)=

P(B) =

12. A manufacturer buys 80% of its materials from Co.K, which

usually has 4% defective. Company L supplies the other 20%

of materials, which usually has 6% defective.

Find probability of a defective item if it came from K. P(D|K)=

Find probability of a defective item if it came from L. P(D|L)=

Find the probability of selecting an item that is both defective

and came from company K.

P(K and D)=

Now, find the probability of selecting an item that is both

defective and came from company K.

P(L and D)=

Now, find the probability of selecting a defective part.

P( D ) =

13. Assume that P(B) = 50%; P(A and B)= 20%; and P(A|B) = 40%

Are A and B independent? Prove

14. 90% of grapes are purple P(P)=.90, of which only

5 % have (M) mold (so 95 % of purple have no mold)

10% of grapes are green P(G)=.10, of which only

8% have mold (so 92% of green have no mold)

Find P(M|P)=

Find P(M|G)=

Find P(P and M)=

Find PG and M)=

Find P(M)=