Question

v. Find the margin of error given the following: 99% confidence interval;

n = 68, x bar = 4156 and Std dev. = 839. ________

a. 1298    b.   237    c. 262    d. 8

vi. When do Type II errors occur?________

a. We decide to reject the null hypothesis when the null hypothesis was actually true.

b.   We fail to reject the null hypothesis when the null hypothesis is actually false.

c.   They occur in both cases.

vii. A standard score of z = 1.00 for an observation means: _________

a. The mean of the distribution lies 1 standard deviations below the observation.

b. The observation lies 1 standard deviations below the mean.

c. The observation lies 1 standard deviations above the mean.

d. The observation lies 1 means below the standard deviation.

viii. Given a 90% and a 95% confidence interval, which of the following is true?

1.   The 90% confidence interval is wider than the 95% confidence interval.
2. There is a better chance that the true mean will be found in the 95% confidence interval.

3. None of the above.

ix. The number of hours per week that high school juniors watch TV is normally distributed with a mean of 8 hours and a standard deviation of 2 hours. If 100 students are chosen at random, find the probability that the mean for that sample is between 8.2 and 8.8

1. 0.1598     b. 0.1586     c. 0.1156    d. 0.1152

Note: standard deviation/ the square root of n.

Check out the Central Limit Theorem

Answer 1