The critical value (z-score) for a 99% confidence interval when the population standard deviation is known
What is 2.58
100
Find the values for t given n = 18 for the 99% confidence interval for the mean
What is 2.898
100
Find the sample proportion given n = 200 and X = 90
What is 0.45
100
What distribution must be used when computing confidence intervals for variances and standard deviations.
What is Chi-square
200
When a 99% confidence interval is calculated instead of a 95% CI with n being the same, the margin of error will be
a) larger
b) smaller
c) the same
d) cannot be determined
What is a) larger
200
Find the t value given n = 15 for the 90% CI for the mean
What is 1.761
200
Find p-hat and q-hat given n = 130 and X = 60
What is 0.46 and 0.54
200
Find the left and right Chi-Square values for a 90% CI with a sample size of 20
What is 10.117 and 30.144
300
A random sample of 49 shoppers showed that they spend an average of $23.45 per visit at the Saturday Mornings Bookstore. The standard deviation of the population is $2.80
Find the 90% CI of the true mean
What is $22.79 < u < $24.11
300
An irate patient complained that the cost of a doctor's visit was too high. She randomly surveyed 20 other patients and found that the mean amount of money they spent on each doctor's visit was $44.80 with a standard deviation of $3.53. Find the 95% CI of the population mean.
What is $43.15 < u < $46.45
300
A recent study of 75 workers found that 53 people rode the bus to work each day. Find the 95% CI for the proportion of all workers of all workers who rode the bus to work.
What is 0.604 < p < 0.810
300
Find the left and right Chi-square values for a 99% CI with a sample size of 6
What is 0.412 and 16.750
400
The average weight of 40 randomly selected mini-vans was 4150 pounds. The standard deviation was 480 pounds. Find the 99% CI of the true mean weight of the minivans
What is 3954.2 < u < 4346.8
400
In a hospital, a sample of 8 weeks was selected, and it was found that an average of 438 patients was treated in the emergency room each week. The standard deviation was 16. Find the 99% CI for the true mean.
What is 418.2 < u < 458.8
400
In a study of 150 accidents that required treatment in an emergency room, 36% involved children under 6 years of age. Find the 90% CI of the true proportion of accidents that involve children under the age of 6.
What is 0.295 < p < 0.425
400
A sample of 25 novels has a standard deviation of 9 pages. Find the 95% CI of the population standard deviation.