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Let's say that for one of the two questions you can narrow the answer choices down to three. Now your chance of getting that question right by guessing is about .33. What is the new expected value for the number of questions you'd get right by guessing?  What are the new variance and standard deviation of this random variable? Drawing another tree diagram and making another probability distribution table may help you answer this question.

Let's say that for one of the two questions you can narrow the answer choices down to three. Now your chance of getting that question right by guessing is about .33. What is the new expected value for the number of questions you'd get right by guessing?  What are the new variance and standard deviation of this random variable? Drawing another tree diagram and making another probability distribution table may help you answer this question.

MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
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Let's say that for one of the two questions you can narrow the answer choices down to three. Now your chance of getting that question right by guessing is about .33.

What is the new expected value for the number of questions you'd get right by guessing? 

What are the new variance and standard deviation of this random variable?

Drawing another tree diagram and making another probability distribution table may help you answer this question. 

(The pictures below are already answer , they are needed to anwer this question)(also zoom in since I could only share 2 pictures)

1. You're taking a multiple-choice exam and you don't know the answers to two of the questions. Each question has five choices, so the probability of getting a question right by guessing is 20. Draw a tree diagram showing the probabilities of getting none, one, or both questions right by guessing. P(x-x) = (2) P²Y/-pn-x X is rendons var jave donets no. of questions quis sed righ non quessed Right [P(x=0) = ( 3 ) x (0₂2)x(1-0,2)/12-07 (0.8)2 Ix0.64 One guessed right P(x-1)=(?)x(0.2) ¹x (1-6.2) (2-1) *72-17 (0.2) ¹x (0.8) = 2x0.2x0.8 = 0.32 One guessed right is 0.32 botiguessed right han quesses right 0.64 P(x-2)=(x(0.27²x(1-0.2) (2-2) =(D) X (0.2) ² X (0.8)° _=1 *0.04 = 0.04 Both guessed right is 0.04 -0.645 (None getting none right by guessing 0.36 One -0.04 Both
Transcribed Image Text:1. You're taking a multiple-choice exam and you don't know the answers to two of the questions. Each question has five choices, so the probability of getting a question right by guessing is 20. Draw a tree diagram showing the probabilities of getting none, one, or both questions right by guessing. P(x-x) = (2) P²Y/-pn-x X is rendons var jave donets no. of questions quis sed righ non quessed Right [P(x=0) = ( 3 ) x (0₂2)x(1-0,2)/12-07 (0.8)2 Ix0.64 One guessed right P(x-1)=(?)x(0.2) ¹x (1-6.2) (2-1) *72-17 (0.2) ¹x (0.8) = 2x0.2x0.8 = 0.32 One guessed right is 0.32 botiguessed right han quesses right 0.64 P(x-2)=(x(0.27²x(1-0.2) (2-2) =(D) X (0.2) ² X (0.8)° _=1 *0.04 = 0.04 Both guessed right is 0.04 -0.645 (None getting none right by guessing 0.36 One -0.04 Both
2. Using the tree diagram you just constructed and make a table showing the probability distribution of getting zero, one, or both questions right by guessing. Probability of choosing a GerreaSUNEY PLO) .20 The leck ability of choosing X. Denates the number of corredh LONGUES XTO,1,3 eine C 10.04 P(x)=0.200.80 020 0:00 0.20 Ⓒ © 2.00 PCK=0,20x0.80 لعليم - P(x=270020×6-20- +(x)=0.80X 0.60 +0.69+ The probability value corresponding to one question is right by guesting thi P(x=1)=0-1640.16 for getting bal, and both right X 0 2 PGTA) 0.64 0.32 0.04 3. Find the expected value of the number of questions you'd get right by guessing. What are the variance and standard deviation? finding the expected welve E(x) = ExP(x^x) 0x0.64+1x0.32 + 2x0.04. 0+0.32+0.08 1-0.40 expected value of probability distribution is 0.40 finding the variance E (x²) xP(x+x) ~0²³ 0.64 + 1²x 0.32+2 x 0.04 V Finding Standard Devention 50 = √Var (X) =√0.32 = 0.545485 €0.5657 SD of probability
Transcribed Image Text:2. Using the tree diagram you just constructed and make a table showing the probability distribution of getting zero, one, or both questions right by guessing. Probability of choosing a GerreaSUNEY PLO) .20 The leck ability of choosing X. Denates the number of corredh LONGUES XTO,1,3 eine C 10.04 P(x)=0.200.80 020 0:00 0.20 Ⓒ © 2.00 PCK=0,20x0.80 لعليم - P(x=270020×6-20- +(x)=0.80X 0.60 +0.69+ The probability value corresponding to one question is right by guesting thi P(x=1)=0-1640.16 for getting bal, and both right X 0 2 PGTA) 0.64 0.32 0.04 3. Find the expected value of the number of questions you'd get right by guessing. What are the variance and standard deviation? finding the expected welve E(x) = ExP(x^x) 0x0.64+1x0.32 + 2x0.04. 0+0.32+0.08 1-0.40 expected value of probability distribution is 0.40 finding the variance E (x²) xP(x+x) ~0²³ 0.64 + 1²x 0.32+2 x 0.04 V Finding Standard Devention 50 = √Var (X) =√0.32 = 0.545485 €0.5657 SD of probability
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