Question

In: Statistics and Probability

In the following problem, check that it is appropriate to use the normal approximation to the...

In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities.

It is known that 77% of all new products introduced in grocery stores fail (are taken off the market) within 2 years. If a grocery store chain introduces 60 new products, find the following probabilities. (Round your answers to four decimal places.)

(a) within 2 years 47 or more fail


(b) within 2 years 58 or fewer fail


(c) within 2 years 15 or more succeed


(d) within 2 years fewer than 10 succeed

Solutions

Expert Solution

Using Normal Approximation to Binomial
Mean = n * P = ( 60 * 0.77 ) = 46.2
Variance = n * P * Q = ( 60 * 0.77 * 0.23 ) = 10.626
Standard deviation = √(variance) = √(10.626) = 3.2598

Part a)
P ( X <= 58 )
Using continuity correction
P ( X < n + 0.5 ) = P ( X < 58 + 0.5 ) = P ( X < 58.5 )

X ~ N ( µ = 46.2 , σ = 3.2598 )
P ( X < 58.5 )
Standardizing the value
Z = ( X - µ ) / σ
Z = ( 58.5 - 46.2 ) / 3.2598
Z = 3.77
P ( ( X - µ ) / σ ) < ( 58.5 - 46.2 ) / 3.2598 )
P ( X < 58.5 ) = P ( Z < 3.77 )
P ( X < 58.5 ) = 0.9999


Part b)
P ( X >= 47 )
Using continuity correction
P ( X > n - 0.5 ) = P ( X > 47 - 0.5 ) =P ( X > 46.5 )

X ~ N ( µ = 46.2 , σ = 3.2598 )
P ( X > 46.5 ) = 1 - P ( X < 46.5 )
Standardizing the value
Z = ( X - µ ) / σ
Z = ( 46.5 - 46.2 ) / 3.2598
Z = 0.09
P ( ( X - µ ) / σ ) > ( 46.5 - 46.2 ) / 3.2598 )
P ( Z > 0.09 )
P ( X > 46.5 ) = 1 - P ( Z < 0.09 )
P ( X > 46.5 ) = 1 - 0.5359
P ( X > 46.5 ) = 0.4641


Part c)
Using Normal Approximation to Binomial
Mean = n * P = ( 60 * 0.23 ) = 13.8
Variance = n * P * Q = ( 60 * 0.23 * 0.77 ) = 10.626
Standard deviation = √(variance) = √(10.626) = 3.2598

P ( X >= 15 )
Using continuity correction
P ( X > n - 0.5 ) = P ( X > 15 - 0.5 ) =P ( X > 14.5 )

X ~ N ( µ = 13.8 , σ = 3.2598 )
P ( X > 14.5 ) = 1 - P ( X < 14.5 )
Standardizing the value
Z = ( X - µ ) / σ
Z = ( 14.5 - 13.8 ) / 3.2598
Z = 0.21
P ( ( X - µ ) / σ ) > ( 14.5 - 13.8 ) / 3.2598 )
P ( Z > 0.21 )
P ( X > 14.5 ) = 1 - P ( Z < 0.21 )
P ( X > 14.5 ) = 1 - 0.5832
P ( X > 14.5 ) = 0.4168


Part d)
P ( X < 10 )
Using continuity correction
P ( X < n - 0.5 ) = P ( X < 10 - 0.5 ) = P ( X < 9.5 )

X ~ N ( µ = 13.8 , σ = 3.2598 )
P ( X < 9.5 )
Standardizing the value
Z = ( X - µ ) / σ
Z = ( 9.5 - 13.8 ) / 3.2598
Z = -1.32
P ( ( X - µ ) / σ ) < ( 9.5 - 13.8 ) / 3.2598 )
P ( X < 9.5 ) = P ( Z < -1.32 )
P ( X < 9.5 ) = 0.0934


Related Solutions

In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 43% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 140 insurance claims to be processed in the next few days. Find...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 39% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 126 insurance claims to be processed in the next few days. Find...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 40% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 120 insurance claims to be processed in the next few days. Find...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 36% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 140 insurance claims to be processed in the next few days. Find...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 36% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 124 insurance claims to be processed in the next few days. Find...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 45% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 124 insurance claims to be processed in the next few days. Find...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 40% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 140 insurance claims to be processed in the next few days. Find...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Ocean fishing for billfish is very popular in the Cozumel region of Mexico. In the Cozumel region about 42% of strikes (while trolling) resulted in a catch. Suppose that on a given day a fleet of fishing boats got a total of 29 strikes. Find the following probabilities. (Round your answers to four...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 37% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 138 insurance claims to be processed in the next few days. Find...
In the following problem, check that it is appropriate to use the normal approximation to the...
In the following problem, check that it is appropriate to use the normal approximation to the binomial. Then use the normal distribution to estimate the requested probabilities. Do you try to pad an insurance claim to cover your deductible? About 37% of all U.S. adults will try to pad their insurance claims! Suppose that you are the director of an insurance adjustment office. Your office has just received 138 insurance claims to be processed in the next few days. Find...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT