0.05. Dally low number of successes: x successes among n trials is an unus numbe
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Question
0.05. Dally low number of successes: x successes among n trials is an unus number of successes if P or fewer)0.05. The value of 0.05 is commonly used but is not absolutely rigid. Other values, such as 0.01, cou distinguish between events that can easily occur by chance and events that are very unlikely to occur by chance. Chapter Quick Quiz 1. Is a probability distribution defined if the only possible values of a random variable are 0, 2, 3, and P(0) P(1) = P(2) = P(3) = 0.25? 2. There are 100 questions from an SAT test, and they are all multiple choice with possible answers of a, b, c, d, e. For each question, only one answer is correct. Find the mean number random guesses for all 100 questions. 3. Using the same SAT questions described in Exercise 2, find the standard deviation for the numbers of correct answers for those who make random guesses for all 100 questions.Explanation / Answer
Ans:
1)Yes,as P(0)+P(1)+P(2)+P(3)=0.25+0.25+0.25+0.25=1
(For a probability distribution to be valid,all probabilities over sample space shuold sum up equal to 1)
2)Binomial distribution with n=100,p=1/5=0.5
(p=probability of success i.e correct answer)
mean=np=100*0.2=20
3)standard deviation=sqrt(np*(1-p))=sqrt(100*0.2*0.8)=4
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