Week 9: HW

Q#1: If the population standard deviation is 15, how large a sample is necessary to have a standard error that is greater than 8 points?

Q#2: IQ scores form a normal distribution with a mean of =100 and a standard deviation of = 15. What is the probability of obtaining a sample mean greater thanM= 100?

a. for a sample ofn= 9 people?

b. for a sample ofn= 25 people?

c. for a sample ofn= 100 people?

Q#3 For a population with a mean of = 50 and a standard deviation of = 14, find thez-score corresponding to each of the following samples.

a. X= 26 for a sample ofn= 1 score

b. M= 26 for a sample ofn= 4 scores

Q#4: Given the data set below find the following; 45, 34, 65, 20, 15, 25, 45 and 69.

a. Compute the sample mean

b. Compute the sample standard deviation

c. Compute the standard error of the mean.

Q#5: Find the estimated standard error for the sample mean forn= 8 andSS= 5042.

week 9 quiz practice

Question 1

If the population standard deviation is 35, how large a sample is necessary to have a standard error that is greater than 13 points?answer to the nearest hundredths place.

Question 2

For a population with a mean of = 67 and a standard deviation of = 8, find thez-score corresponding to the sample mean M= 44 and sample size n = 7 scores.

Question 3

IQ scores form a normal distribution with a mean of =105 and a standard deviation of = 11. What is the probability of obtaining a sample mean greater than M = 107 for a sample of n = 30 people?

A. 1.0000

B. 0.9893

C. 0.1587

D. 0.8412

Question 4

Compute the standard error of the mean from the following scores; 45, 34, 65, 13, 15, 25.

Round your answer to the nearest hundredths.

Question 5

Find the estimated standard error for the sample mean forn= 19 andSS= 3996. Round to the nearest hundredths.