review sheet 8, 11-19, 25 obj: review for probability quest 2

Review Sheet 8, 11-19, 25

OBJ: Review for Probability Quest 2

1. Two cards are chosen at random from a deck of 52 cards without replacement. What is the probability of getting two kings? 4/663 1/221 1/69 None of the above4/52 · 3/51 = 12/2652 = 1/221

Two cards are chosen at random from a deck of 52 cards without replacement. What is the probability that the first card is a jack and the second card is a ten?3/676 1/169 4/663 None of the above4/52 · 4/51 = 16/2652 = 4/663

On a math test, 5 out of 20 students got an A. If three students are chosen at random without replacement, what is the probability that all three got an A on the test? 1/114 25/1368 3/400 None of the above5/20 · 4/19 · 3/18 =60/6840 = 1/114 Three cards are chosen at random from a deck of 52 cards without replacement. What is the probability of getting an ace, a king and a queen in order?1/2197 8/5525 8/16575 None of the above4/52 · 4/51 · 4/50 = 64/132600 = 8/16575

A school survey found that 7 out of 30 students walk to school. If four students are selected at random without replacement, what is the probability that all four walk to school? 343/93960 1/783 7/6750 None of the above

7/30 · 6/29 · 5/28 · 4/27 =840/657720 = 1/783

13. One card is drawn from a regular deck. What is the probability that it is a queen if it is known to be a face card?P(Q/F) = n(Q and F)/n(F) ( = P(Q and F)/P(F)) = 4 12= 1 3

In New York State, 48% of all teenagers own a skate board, and 39% of all teenagers have roller blades and a skate board. What is the probability that a teenager who has roller bladesalso has a skate board? 87% 81% 123% None of the above

P( SB/ RB) = P(SB RB)/P(RB) = .39 ÷ .48 = .8125

At a middle school, 18% of all students play football and basketball, and 32% of all students play football. What is the probability that a student who plays football also plays basketball?56% 178% 50% None of the above

P( BB/ FB) = P(BB F B)/P(FB) = .18 ÷ .32 = .5625

In the United States, 56% of all children get an allowance, and 41%of all children get an allowance and do household chores. What is the probability that a child does household chores given that he/she gets an allowance? 137% 97% 73% None of the above

P( HC/ AL) = P(HC AL)/P(AL) = .41 ÷ .56 = .7321

In Europe, 88% of all households have a television. 51% of all households have a television and a VCR. What is the probability that a houshold with a television also has a VCR?173% 58% 42% None of the above

P(VCR/ TV) = P(VCR TV/P(TV) = .51 ÷ .88 = .5795In New England, 84% of the houses have a garage. 65% of the houses have a back yard and a garage. What is the probability that a house has a backyard given that its has a garage? 77% 109% 19% None of the above

P(G/ BY) = P(G BY/P(BY) = .65 ÷ .84 = .7738

12) A pair of dice is thrown. Find the probability that the dice match, given that their sum is greater than five. P(dice match/sum >5)= 4 26= 2 13

(1,5) (1,6)

(2,4) (2,5) (2,6)(3,3) (3,4) (3,5) (3,6)

(4,2) (4,3) (4,4) (4,5) (4,6)(5,1) (5,2) (5,3) (5,4) (5,5) (5,6)(6,1) (6,2) (6,3) (6,4) (6,5) (6,6)

14. A pair of dice is thrown. Given that their sum is > 9, finda. P(sum is 8)

0b. P(numbers match) 2 = 1

10 5c. P(sum is 12) 1

10d. P(sum is even) 4 = 2

10 5e. P(sum is 9 or 10)

7 10f. P(numbers match or sum is even)

2 + 4 _ 2 10 10 10 2/5

9

9 10

9 10 11

9 10 11 12

8)There are 4 navy socks and 6 black socks in your drawer. One dark morning you randomly select 2 socks. What is the probability that you will choose a navy pair?

• With Replacement 4 • 4_10 10 2 • 2_ 5 5 4_ 25

• Without Replacement

4 • 310 9 2 • 1_ 5 3 2_ 15

25. There are 8 girls and 5 boys in my class. If I randomly select 4 students to go to the board, find the following (Use combination notation)

a. P(all girls) =

8C4 •5C0

13C4

b. P(2 girls and 2 boys) =

8C2 •5C2

13C4

c. P(1 girl and 3 boys) =

8C1 •5C3

13C4

The students that go to the board are to be 2 seniors and 2 juniors, who are to be chosen at random from the 6 seniors and 7 juniors. If half of the seniors and 4 juniors are girls find the probability that only girls go up to the board(Use combination notation)

3C2 •3C0 •4C2 •3C0

13C4

19a. (2c – 1)5

1( )5 – 5( )4 + 10( )3 – 10( )2 + 5( )1 – 1 1(2c)5 – 5(2c)4 + 10(2c)3 – 10(2c)2 + 5(2c)1– 132c5 – 5(16c4) + 10(8c3) – 10(4c2) + 5(2c) – 132c5 – 80c4 + 80c3 – 40c2 + 10c – 1

19b. third term of (3x + 2y)6

1( )6 + 6( )5( )1 + 15( )4( )2

15(3x)4(2y)2

15(81x4)(4y2)4860x4y2

16.While pitching for the Toronto Blue Jays, 4 out of every 7 pitches that Juan Guzman threw in the first five innings were strikes. Find the probability that three of his next four pitches will be strikes.

nCk pk(1-p)n-k

n=4, k=3, p=4/7,1-p=3/7 4C3(4/7)3(3/7)1=

4 (43/73) (3/7)=44•3 = 768 74 2401

From HW 66. What is the probability of

getting K #s in N rolls of a die?P = 1/61-P = 5/6

9. A quiz has N multiple-choice questions, each with # choices. What is the probability of getting K choices correct?

P = 1/#1-P = 1- 1/#

17. Maria guessed at all 10 true/false questions on her math test. Find:

a. P(7 correct) =

nCk pk(1-p)n-k

n=10, k=7, p=1/2, 1-p=1/2

10C7(1/2)7(1/2)3 =

120 110 = 210

120 =1024 15128b. P(all incorrect) =

nCk pk(1-p)n-k

n=10, k=0, p=1/2, 1-p=1/2

10C0(1/2)0(1/2)10 =

1 110 = 210

1__1024

c. P(at least 6 correct) =

nCk pk(1-p)n-k

n=10, k > 6, p=1/2, 1-p=1/2

10C6(1/2)6(1/2)4 +

10C7(1/2)7(1/2)3 +

10C8(1/2)8(1/2)2 +

10C9(1/2)9(1/2)1 +

10C10(1/2)10(1/2)0

15)A dollar bill changer was tested with 100 one-dollar bills, of which 25 were counterfeit and the rest were legal. The changer rejected 30 bills, and 6 of the rejected bills were counterfeit. Construct a table, then find

a. Incorporate the facts given above into a

conditional chart.R R

CC



conditional chart.R R

C 6 25

C30 100


R RC 6 19 25

C 24 51 75

30 70 100


R RC 6 19 25

C 24 51 75

30 70 100

R RC 6 25

C30 100

15)A dollar bill changer was tested with 100 one-dollar bills, of which 25 were counterfeit and the rest were legal. The changer rejected 30 bills, and 6 of the rejected bills were counterfeit. Construct a table, then finda. The probability that a bill is legal

and it is accepted by the machine. P(CR)= 51 100b. The probability that a bill is

rejected, given it is legal. P(R/C)= 24 = 8

75 25c. The probability that a counterfeit

bill is not rejectedP(R/C) = 19

25

R RC 6 19 25

C 24 51 75

30 70 100

11)Of 200 students surveyed, 100 said they studied for their math test. 105 said they passed their test, and 80 said they studied and passed their test.


conditional chart.P P

SS



conditional chart.P P

S 80 100

S105 200


P PS 80 20 100

S 25 75 100

105 95 200

P PS 80 100

S105 200


P PS 80 20 100

S 25 75 100

105 95 200

a) P(pass)1052002140


P PS 80 20 100

S 25 75 100

105 95 200

b) P(pass/studied) P(P/S) 80100 4 5


P PS 80 20 100

S 25 75 100

105 95 200

_ _c) P(P/S) 75100 3 4

18. The probability that a certain softball player gets a hit is 1/5. (20%) In her next 5 at bats, find

b. P( at least 4 hits)

nCk pk(1-p)n-k

n = 5, k ≥ 4, p = .2, 1–p=.8

5C4 (.2)4 (.8)1 + 5C5 (.2)5

c. P(at least 1 hit)

nCk pk(1-p)n-k

n = 5, k ≥ 1, p = .2, 1–p=.8

5C1 (.2)1 (.8)4+5C2 (.2)2 (.8)3

5C3 (.2)3 (.8)2 + 5C4(.2)4 (.8)1

+ 5C5 (.2)5 OR

1 – 5C0 (.8)5

The problem on the quest, n=10!!!

From HW 12 Conditional Worksheet 1. In a study of the reading habits of 250 college students it was found that 158 read Time magazine, 139 read Newsweek, and 100 read both Time and Newsweek


conditional chart.T T

NN


Incorporate the facts given above into a

conditional chart.T T

N 100 139

N158 250


T TN 100 39 139

N 58 53 111

158 92 250

T TN 100 139

N158 250

From HW 12 Conditional Worksheet 1. In a study of the reading habits of 250 college students it was found that 158 read Time magazine, 139 read Newsweek, and 100 read both Time and Newsweek. Find the probability that a student:a. Reads Newsweek P(N)

139

250b. Reads both Time and

Newsweek P(T N) 100

2 250

5

T TN 100 39 139

N 58 53 111

158 92 250

From HW 12 Conditional Worksheet 1. In a study of the reading habits of 250 college students it was found that 158 read Time magazine, 139 read Newsweek, and 100 read both Time and Newsweek. Find the probability that a student:c. Reads Newsweek given

reads Time P(NT) 100

50 158

79d. Read Time given reads

Newsweek P(T/N) 100/139

T TN 100 39 139

N 58 53 111

158 92 250

From HW 12 Conditional Worksheet 4.Out of 1000 students surveyed, 10% reported that they had had a car accident since getting their license, 40% reported driving more than 10,000 miles since getting their license and 6% had driven more than 10,000 miles and had an accident.


conditional chart.A A

MM



conditional chart.A A

M 60 400

M100 1000



conditional chart.

A AM 60 340 400

M 40 560 600

100 900 1000

From HW 12 Conditional Worksheet 4.Out of 1000 students surveyed, 10% reported that they had had a car accident since getting their license, 40% reported driving more than 10,000 miles since getting their license and 6% had driven more than 10,000 miles and had an accident

A AM 60 340 400

M 40 560 600

100 900 1000

A AM 60 400

M100 1000

From HW 12 Conditional Worksheet 4.Out of 1000 students surveyed, 10% reported that they had had a car accident since getting their license, 40% reported driving more than 10,000 miles since getting their license and 6% had driven more than 10,000 miles and had an accident. Find the probability that a student

a. Had driven more than 10000 miles without having an accident. P(M A) 340 17 1000 50

b. Had driven no more than 10000 miles and did not have an __ accident. P(M A)

560 14 1000 25

A AM 60 340 400

M 40 560 600

100 900 1000

From HW 12 Conditional Worksheet 4.Out of 1000 students surveyed, 10% reported that they had had a car accident since getting their license, 40% reported driving more than 10,000 miles since getting their license and 6% had driven more than 10,000 miles and had an accident. Find the probability that a student

c. Who drove no more than 10,000 miles had an accident. P(M/A) 40 1

600 15d. Who did not have an

accident drove more than 10,000 miles.

P(A/M) 340/900=17/45

A AM 60 340 400

M 40 560 600

100 900 1000

review sheet 8, 11-19, 25 obj: review for probability quest 2

Documents