Question

1.)A population of values has a normal distribution with μ=14 and σ=28. You intend to draw a random sample of size n=53

Find the probability that a single randomly selected value is less than 22.5.

Find the probability that a sample of size n=53 is randomly selected with a mean less than 22.5.

2.)A company produces steel rods. The lengths of the steel rods are normally distributed with a mean of 149.3-cm and a standard deviation of 1-cm. For shipment, 6 steel rods are bundled together. Find P20, which is the average length separating the smallest 20% bundles from the largest 80% bundles. p20=

3.)A company produces steel rods. The lengths of the steel rods are normally distributed with a mean of 124.8-cm and a standard deviation of 1.4-cm. For shipment, 22 steel rods are bundled together. Find the probability that the average length of a randomly selected bundle of steel rods is between 123.8-cm and 124.9-cm.

P(123.8-cm < M < 124.9-cm

4.)A company produces steel rods. The lengths of the steel rods are normally distributed with a mean of 245.8-cm and a standard deviation of 1.5-cm. For shipment, 17 steel rods are bundled together. Find the probability that the average length of a randomly selected bundle of steel rods is greater than 246.2-cm.

P(M > 246.2-cm

Answer 1