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tjoy
Apr 11, 2012, 09:06 AM
Suppose you are told that average height of a person at your school is 57 inches from a sample with a population standard deviation of 3 inches. If you take a sample of 49 students use this info to calculate the following
A. Determine the standard error of the mean
B. Determine a 95% confidence interval estimate for the mean height of people at your school.

If you are given that the proportion of students at your school who like to attend college is 60% from a sample of 49.
C. Find the standard deviation of the proportion
D. Use your value in part c to find a 90% CI for students who actually like to attend college

Please explain how you got your answers.

tjoy
Apr 11, 2012, 09:13 AM
You are given the following info obtained from a random sample of 5 observations. X={20, 18, 17, 22, 18} At 95% confidence, you want to determine whether the population from which this sample was taken is significantly less than 23. (Assume the population is normally distributed.)

A. State the null and the alternative hypothesis
B. Compute the standard error of the mean. Hint: You need the mean and standard deviation of the sample which are: 19 and 2 respectively.
C. Determine the test statistic
D. Test to determine whether the mean of the population is significantly less than 23.

Please explain how you got to answers.

tjoy
Apr 11, 2012, 11:52 AM
You are given the following info obtained from a random sample of 5 observations. X={20, 18, 17, 22, 18} At 95% confidence, you want to determine whether the population from which this sample was taken is significantly less than 23. (Assume the population is normally distributed.)

A. State the null and the alternative hypothesis
B. Compute the standard error of the mean. Hint: You need the mean and standard deviation of the sample which are: 19 and 2 respectively.
C. Determine the test statistic
D. Test to determine whether the mean of the population is significantly less than 23.

Please explain how you got to answers.

tjoy
Apr 12, 2012, 08:50 AM
Suppose you are told that average height of a person at your school is 57 inches from a sample with a population standard deviation of 3 inches. If you take a sample of 49 students use this info to calculate the following
A. Determine the standard error of the mean
B. Determine a 95% confidence interval estimate for the mean height of people at your school.

If you are given that the proportion of students at your school who like to attend college is 60% from a sample of 49.
C. Find the standard deviation of the proportion
D. Use your value in part c to find a 90% CI for students who actually like to attend college

Please explain how you got your answers.

tjoy
Apr 12, 2012, 09:42 AM
A manufacturer of cordless electric shavers sampled 13 from a day's production and found the mean time of continuous usage without recharging to be 410 minutes with a sample standard deviation of 30 minutes. We can assume that times are normally distributed. We wish to test if the true mean operating time without recharging is more than 400 minutes.

1. State the null and alternative hypotheses

2. The correct conclusion at the 0.05 level of significance is
I. Reject the null hypothesis
II. Do not reject the null hypothesis
III. Evidence suggests that the mean operating time is more than 400 minutes.
A. III
B. II
C. I and III
D. II and III
E. I

3. The correct calculated value of the test statistic is
A. -1.20
B. 1.20
C. 2.79
D. -2.52
E. -0.333

Please explain how you got the answers.

Curlyben
Apr 12, 2012, 09:44 AM
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tjoy
Apr 12, 2012, 09:47 AM
Absorption rates into the body are important considerations when manufacturing a generic version of a brand name drug. A pharmacist read that the absorption rate into the body of a new generic drug (G) is the same as its brand name counterpart (B). She has a researcher friend of hers run a small experiment to test Ho:uG-uB=0 against the alternative Ha: uG-uB=0. Which of the following would be a Type 1 error?

A. Deciding that the absorption rates are the same, when in fact they are.
B. Deciding that the absorption rates are different, when in fact they are not.
C. Deciding that the absorption rates are the same, when in fact they are not.
D. Deciding that the absorption rates are different, when in fact they are.
E. The researcher cannot make a type 1 error, since he has run an experiment.

Please explain how you got the answer.