A population of values has a normal distribution with μ=25.1 and σ=18.2. You intend to draw a random sample of size n=129 Find P 90 , which is the mean separating the bottom 90% means from the top 10%...

A company produces steel rods. The lengths of the steel rods are normally distributed with a mean of 252.2-cm and a standard deviation of 1.4-cm. For shipment, 20 steel rods are bundled together.


Find the probability that the average length of a randomly selected bundle of steel rods is greater than 252.9-cm.


P(M
> 252.9-cm) =



Enter your answer as a number accurate to 4 decimal places. Answers obtained using exact
z-scores or
z-scores rounded to 3 decimal places are accepted.