Solution:
Solution
Given that,
P( -zc < Z < zc ) = 0.85
P( Z < zc ) - P( Z < -zc ) = 0.85
2*P(Z < z ) - 1 = 0.85
2*P(Z < z ) = 1 + 0.85
P( Z < z ) = 1.85/ 2
P( Z < z ) = 0.925
P( Z < 1.4395) = 0.925
zc = 1.4395
and
-zc = -1.4395
N(0,1) For the picture above, which shows the standard normal curve with critical values marked, if...
For the picture above, which shows the standard normal curve
with critical values marked, if c=0.85, then zc= .
(Round your answer to four decimal places.)
N(0,1) YLC
Lecture 19: Problem 9 Problem List Next Previous (1 point) A market research company wanting to determine the average quantity of nuts eaten per year by Americans interviewed 730 Americans and found a sample mean of 3.85 lb. If the company knows that the population standard deviation is 0.85, what is the 92% confidence interval for the population mean? Round your answers to two decimal places. Note: You can earn partial credit on this problem. Note: You can get a...
Lecture 19: Problem 1. Previous Problem List Next (1 point) The table below shows the lengths of some randomly chosen CDs in John's very large collection. Give the 93% confidence interval for the population mean, assuming that the population is approximately normally distributed. Round the endpoints to two decimal places. 53.47 64.0935.87 64.78 47.13 67.85 38.29 39.02 39.77 44.89 37.96 37.91 74.12 67.82 57.31 60.52 68.88 54.76 57.78 56.38 43.77 54.23 38.21 59.32 71.33 Confidence interval: Note: You can earn...
Lecture19: Problem 10 Previous Problem List Nest (1 point) Compute, to three decimal places, a 90% confidence interval for the mean of a population with o = 24.2, given that a sample of size 50 had a mean of 52.5. Confidence interval: Note: You can earn partial credit on this problem. Note: You can get a new version of this problem after the due date. Preview My Answers Submit Answers
Lecture18: Problem 7 Previous Problem List Next (1 point) The diameter of the twelve-penny common nails made by 'Snails!, Inc., is normally distributed with standard deviation 0.004 in. A sample of 37 such nails was found to have a mean diameter of 0.127 in. Find a 90% confidence interval for the mean diameter of all such nails. Round the endpoints to five decimal places. Confidence interval is ( Note: You can earn partial credit on this problem. Note: You can...
Lecture19: Problem 2 Previous Problem List Next (1 point) John measured the total playing time of 25 randomly chosen CDs from his very large collection and found a mean of 65.2 minutes and a standard deviation of 11.4 minutes. Give the 97% confidence interval for the population mean, assuming that the population is approximately normally distributed. Round the endpoints to two decimal places. Confidence interval:( Note: You can earn partial credit on this problem. Note: You can get a new...
Lecture19: Problem 4 Previous Problem List Next (1 point) 1Q tests are designed so that the mean is 100 points and the standard deviation is 15 points for the entire adult population. What is the minimum sample size needed to estimate the average IQ of all Stat 200 students to within 3 points with 96% confidence? Note: You can get a new version of this problem after the due date. Preview My Answers Submit Answers
Lecture 18: Problem 6 Previous Problem List Next (1 point) The average starting salaries for 50 graduates with a certain major was $43947. The standard deviation for all graduates with that major was $8681. Give the 93% confidence interval for the population mean. Round the endpoints to the nearest dollar, and do not put commas in your numbers. Confidence interval: Note: You can earn partial credit on this problem. Note: You can get a new version of this problem after...
Lecture19: Problem 5 Previous Problem List Next (1 point) A long history of testing water samples in a certain lake has shown that the level of a certain pollutant is approximately normally distributed with standard deviation 4.9 mg/L. What is the minimum number of samples required to estimate today's level to with in 0.6 mg/L with 91% confidence? ZC = 1.7 n = 193 Note: You can get a new version of this problem after the due date. Preview My...
Lecture18: Problem 9 Previous Problem List Next (1 point) If 450 confidence intervals, each having a 97% level of confidence, were computed for a population mean u about how many of the intervals can be expected to contain u? (Your answer will be an integer, of course.) Note: You can get a new version of this problem after the due date. Preview My Answers Submit Answers