Answer:
The probability that a random sample of n = 5 specimens will have a sample values that falls in the interval from 2499 psi to 2510 psi = P(2499 < x < 2510) = 0.192
Step-by-step explanation:
For the population,
μ = 2500 psi and σ = 50 psi
But for a sample of n = 5
μₓ = μ = 2500 psi
σₓ = σ/√n = (50/√5)
σₓ = 22.36 psi
So, probability that the value for the sample falls between 2499 psi to 2510 psi
P(2499 < x < 2510)
We normalize/standardize these values firstly,
The standardized score for any value is the value minus the mean then divided by the standard deviation.
For 2499 psi
z = (x - μ)/σ = (2499 - 2500)/22.36 = - 0.045
For 2510 psi
z = (x - μ)/σ = (2510 - 2500)/22.36 = 0.45
To determine the probability the value for the sample falls between 2499 psi to 2510 psi
P(2499 < x < 2510) = P(-0.045 < z < 0.45)
We'll use data from the normal probability table for these probabilities
P(2499 < x < 2510) = P(-0.045 < z < 0.45) = P(z < 0.45) - P(z < -0.045) = 0.674 - 0.482 = 0.192
