Questions from Engineering Statistics

Q: The grade-point averages of 20 college seniors selected at random

The grade-point averages of 20 college seniors selected at random from a graduating class are as follows: Calculate the standard deviation.

Q: (a) Show that the sample variance is unchanged if a

(a) Show that the sample variance is unchanged if a constant c is added to or subtracted from each 232 Chapter 8 Fundamental Sampling Distributions and Data Descriptions value in the sample. (b) Show...

Q: Verify that the variance of the sample 4, 9, 3

Verify that the variance of the sample 4, 9, 3, 6, 4, and 7 is 5.1, and using this fact, along with the results of Exercise 8.14, find (a) the variance of the sample 12, 27, 9, 18, 12, and 21; (b) th...

Q: In the 2004-05 football season, University of Southern California

In the 2004-05 football season, University of Southern California had the following score differences for the 13 games it played. Find (a) the mean score difference; (b) the median score differences...

Q: If all possible samples of size 16 are drawn from a normal

If all possible samples of size 16 are drawn from a normal population with mean equal to 50 and standard deviation equal to 5, what is the probability that a sample mean ¯X will fall in the interval f...

Q: If the standard deviation of the mean for the sampling distribution of

If the standard deviation of the mean for the sampling distribution of random samples of size 36 from a large or infinite population is 2, how large must the sample size become if the standard deviati...

Q: A certain type of thread is manufactured with a mean tensile strength

A certain type of thread is manufactured with a mean tensile strength of 78.3 kilograms and a standard deviation of 5.6 kilograms. How is the variance of the sample mean changed when the sample size i...

Q: The lengths of time, in minutes, that 10 patients waited

The lengths of time, in minutes, that 10 patients waited in a doctor’s office before receiving treatment were recorded as follows: 5, 11, 9, 5, 10, 15, 6, 10, 5, and 10. Treating the data as a random...

Q: In a study conducted by the Department of Zoology at Virginia Tech

In a study conducted by the Department of Zoology at Virginia Tech, fifteen samples of water were collected from a certain station in the James River in order to gain some insight regarding the amount...

Q: Given the discrete uniform population / find the

Given the discrete uniform population find the probability that a random sample of size 54, selected with replacement, will yield a sample mean greater than 4.1 but less than 4.4. Assume the means a...