A sample of n = 4 scores is selected from a normal population with a mean of µ = 50 and a standard deviation of σ = 20. What is the probability of obtaining a sample mean greater than M = 48? a.           p = 0.6554          c.           p = 0.5793 b.           p = 0.3446          d.           p = 0.4207

A machine produces glass with a nominal thickness of 4mm. In fact the thickness is a Normal random variable with mean 4.168mm and standard deviation 0.12mm. The thickness in mm which 5% of panes exceed is (2 d.p.)?

A population of values has a normal distribution with μ=240.1 and σ=82.8. A random sample of size n=33 is drawn. What is the mean of the distribution of sample means ? What is the standard deviation of the distribution of sample means?

The mean score on a driving exam for a group of driver’s education students is 76 points, with a standard deviation of 6 points. Apply chebychev’s theorem to the data using K=2. Interpret, At least ___% of the exam score falls between ___and ____

Consider a population distribution of means that come from a normal distribution. The mean of the score distribution(μ)=100 and the standard deviation (σX) =10 and the means are from sample size=16. What is the proportion of means above a means of102.5?

For a sample, a score that is 12 points above the mean has a z-score of z = 1.20. What is the sample standard deviation?

An independent random sample is selected from an approximately normal population with an unknown standard deviation. Find the p-value for the given sample size and test statistic. a. n = 11, T = 1.91 b. n = 17, T = -3.45 c. n = 26, T = 2.485 d. n = 18, T = 0.5

The length of time on the SAT exam for a group of students is normally distributed with a mean of 2.5 hours and a standard deviation of 0.25 hours. A sample size of n= 60 is drawn randomly from the population. Find the probability that the sample mean is between two hours and three hours.

The grade point average for ALL juniors at a large college has a standard deviation of 0.50.  A random sample of 20 students is to be used to estimate the population mean grade point average.  What condition do you need to verify prior to computing the probability of obtaining a sample mean within plus or minus 0.2 of the population mean?