A balanced coin is tossed three times. Let Y equal the

Chapter 3, Problem 173E

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QUESTION:

Problem 173E

A balanced coin is tossed three times. Let Y equal the number of heads observed.

a Use the formula for the binomial probability distribution to calculate the probabilities associated with Y = 0, 1, 2, and 3.

b Construct a probability distribution similar to the one in Table 3.1.

c Find the expected value and standard deviation of Y, using the formulas E(Y ) = np and V (Y ) = npq.

d Using the probability distribution from part (b), find the fraction of the population measurements lying within 1 standard deviation of the mean. Repeat for 2 standard deviations. How do your results compare with the results of Tchebysheff’s theorem and the empirical rule?

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QUESTION:

Problem 173E

A balanced coin is tossed three times. Let Y equal the number of heads observed.

a Use the formula for the binomial probability distribution to calculate the probabilities associated with Y = 0, 1, 2, and 3.

b Construct a probability distribution similar to the one in Table 3.1.

c Find the expected value and standard deviation of Y, using the formulas E(Y ) = np and V (Y ) = npq.

d Using the probability distribution from part (b), find the fraction of the population measurements lying within 1 standard deviation of the mean. Repeat for 2 standard deviations. How do your results compare with the results of Tchebysheff’s theorem and the empirical rule?

ANSWER:

Solution 123E

Step1 of 5:

Let us consider a random variable Y it presents the number of heads observed.

Also we have n = 3.

Here our goal is:

a). We need to calculate the probabilities associated with Y = 0, 1, 2, and 3. By using Use the formula for the binomial probability distribution.

b). We need to construct a probability distribution similar to the one in Table 3.1.

c). We need to find the expected value and standard deviation of Y, using the formulas

E(Y ) = np and V (Y ) = npq.

d). We need to find the fraction of the population measurements lying within 1 standard deviation of the mean. Repeat for 2 standard deviations. And also compare with the results of Tchebysheff’s theorem and the empirical rule.


Step2 of 5:

a).

Probability of getting head is given by:

      =  

Here Y follows binomial distribution with parameter ‘n and p’.

That is YB(n, p)

                 YB(3, 0.5)

Then the probability mass function of binomial distribution is given by:

Where,

y = random variable

p = probability of success

n = sample size

Now,

For Y = 0 the probability is given  by:

       

         

Hence, P(Y = 0) = 0.1250.

For Y = 1 the probability is given  by:

     

       

Hence, P(Y = 1) = 0.3750.

For Y = 2 the probability is given  by:

 

       

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