the population standard deviation of the lifetime of washing machines is estimated to be 900 hours, how large a sample must be taken in order to be 90% confident that the margin of error will not exceed 100 hours?
Select one:
a. 219.18
b. 220
c. 14.8
d. 15
the population standard deviation of the lifetime of washing machines is estimated to be 900 hours,...
If the population standard deviation of the lifetime of washing machines is estimated to be 900 hours, how large a sample must be taken in order to be 90% confident that the margin of error will not exceed 100 hours? Select one: a. 219.18 b. 220 c. 14.8 d. 15
It is known that the population standard deviation of an aptitude test score is 72. How large a sample must be taken in order to be 90% confident that the margin of error will not exceed 15?
1)A random sample of 225 observations showed a mean of 25. The population variance is 961 Compute the lower limit of the 93% confidence interval. NOTE: WRITE YOUR ANSWER WITH 4 DECIMAL DIGITS. DO NOT ROUND UP OR DOWN. 2) If the population standard deviation of the lifetime of a vacuum cleaner is 300 hours, how large of a sample must be taken in order to be 90% confident that the margin of error will not exceed 50 hours?
QUESTION 15 A statistician employed by a consumer testing organization reports that at 95% confidence he has determined that the true average content of the Uncola soft drinks is between 12.714 to 13.286 ounces, but he forgot to report the size of the sample he had selected. Assuming the standard deviation of the population is 1.21, determine the size of the sample. (NOTE: ROUND YOUR ANSWER TO THE NEAREST INTEGER) QUESTION 16 If the population variance of the lifetime of...
The owner of a restaurant wants to determine the average number of customers who eat lunch at his restaurant each day. A sample of 16 days showed that an average of 130 lunches were served daily. The standard deviation of the sample was 12, Provide a 90% confidence interval estimate for the average number of lunches served per day. If the standard deviation for lifetimes of vacuum cleaners is estimated to be 400 hours, how large a sample must be...
2) A manufacturer wishes to estimate the proportion of washing machines leaving the factory that are defective. How large a sample should she check in order to be 90% confident that the true proportion is estimated to within 4%?
problems 4, 5, 6, 11 and 13 If the population standard deviation was doubled to 10.4 and the level of confidence remained at 90%, what would be the new margin of error and confidence interval Margin of error, E. Confidence interval: 20.11<x<34.31 O Did the confidence interval increase or decrease and why? increase 4. Definition of Confidence Intervals (Section 6.1) Circle your answer, True of False. • A 99% confidence interval means that there is a 99% probability that the...
Westinghouse wants to determine the lifetime of its standard lightbulbs with an error 13 hours. Standard deviation is 120 hours. What sample size should they have to be 95% confident of the lifetime of their standard lightbulb? a) 18.09 lightbulbs b) 19 lightbulbs c) 328 lightbulbs d) 327.33 lightbulbs
A population has standard deviation - 17.3. Part 1 of 2 (a) How large a sample must be drawn so that a 99.9% confidence interval for ji will have a margin of error equal to 3.7? Round the answer up to the nearest integer. (Round the critical value to no less than three decimal places.) A sample size of is needed to be drawn in order to obtain a 99.9% confidence interval with a margin of error equal to 3.7....
A population has standard deviation o-17.3. al. Part 1 of 2 1 (a) How large a sample must be drawn so that a 95% confidence interval for u will have a margin of error equal to 4.5? Round the critical value to no less than three decimal places. Round the sample size up to the nearest integer. A sample size of is needed to be drawn in order to obtain a 95% confidence interval with a margin of error equal...