An electrical firm manufactures light bulbs that have a length of life that is approximately norm...
An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 20 hours. If a sample of 30 bulbs has an average life of 780 hours, how large a sample is needed if we wish to be 95% confident that our sample mean will be within 4 hours of the true mean.
| a. |
62 |
|
| b. |
68 |
|
| c. |
100 |
|
| d. |
97 |
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An electrical firm manufactures light bulbs that have a length of life that is approximately norm...
An electrical firm manufactures light bulbs that have a length of life that is approximately normally...
An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 20 hours. If a sample of 30 bulbs has an average life of 780 hours, how large a sample is needed if we wish to be 95% confident that our sample mean will be within 4 hours of the true mean. a. 62 b. 68 c. 100 d. 97
An electrical firm manufactures light bulbs that have a length of life that is approximately normally...
An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 40 hours. If a sample of 30 bulbs has an average life of 780 hours, find a 96% confidence interval for the population mean of all bulbs produced by this firm. How large a sample is needed if we wish to be 96% confident that our sample mean will be within 10 hours of the true mean?
An electrical firm manufactures light bulbs that have a length of life that is approximately normally...
An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 25 hours. If we wish to be 99% confident that the sample mean will be within 4 hours of the true mean, how large a sample is needed? At least observations.
9.2 An electrical firm manufactures light bulbs that have a length of life that is approximately...
9.2 An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 40 hours. If a sample of 30 bulbs has an average life of 780 hours, find a 96% confidence interval for the population mean of all bulbs produced by this firm. Many cardiac patients wear an implanted pace- maker to control their heartbeat. A plastic connec- tor module mounts on the top of the pacemaker. As- suming...
A n electrical firm manufactures light bulbs that have a length of life that is approximately...
A n electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a sample standard deviation of 40 hours. If a sample of 16 bulbs has an average life of 770 hours, find a 95% two-sided confidence interval for the population mean of all bulbs produced by this firm. a. 750.40 < µ < 789.60 b. 752.47 < µ < 787.53 c. 761.47 < µ < 796.53 d. 748.69 < µ < 791.31
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a standard deviation of o = 10 hours. A sample of size n = 100 is obtained, and its sample mean is calculated to be I = 320 hours. Find the 95% confidence interval for the average length life p. Find the upper 95% bound for the average length life u. Find the lower 95% bound for the average length life u. Give your answer...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a standard deviation of o = 40 hours. A sample of size n = 100 bulbs has an average life of 740 hours. Find the 95% confidence interval for the population mean of all bulbs produced by this firm. (use interval notation). What z value(s) did you use to calculate the confidence interval above? Explain why briefly.
1. An electric firm manufactures light bulbs that have a lifetime, X, that is approximately norma...
1. An electric firm manufactures light bulbs that have a lifetime, X, that is approximately normally distributed with a standard deviation of 100 hours. Prior experience leads the firm to establish that the mean of X (or mean lifetime), say , follows a normal distribution with mean 140-800 hours and standard deviation σ0 10 hours. If a random sample of 25 bulbs examined turns out an average lifetime of 780 hours, solve the following. (a) Find a 95% Bayesian estinate...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a standard deviation of o = 40 hours. A sample of size n = 100 bulbs has an average life of 650 hours. Find the lower 99% confidence bound for the population mean of all bulbs produced by this firm. (use interval notation). What z value (s) did you use to calculate the confidence interval above? Explain why briefly.
An electrical firm manufactures light bulbs that have a length life with normal distribution, and mean...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and mean equal to 800 hours, and a variance of 8. Find the probability that a random sample of 29 light bulbs will have a sample variance S2 between 7.81 and 16.25.
An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 25 hours. If we wish to be 99% confident that the sample mean will be within 4 hours of the true mean, how large a sample is needed? At least observations.
9.2 An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 40 hours. If a sample of 30 bulbs has an average life of 780 hours, find a 96% confidence interval for the population mean of all bulbs produced by this firm. Many cardiac patients wear an implanted pace- maker to control their heartbeat. A plastic connec- tor module mounts on the top of the pacemaker. As- suming...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a standard deviation of o = 10 hours. A sample of size n = 100 is obtained, and its sample mean is calculated to be I = 320 hours. Find the 95% confidence interval for the average length life p. Find the upper 95% bound for the average length life u. Find the lower 95% bound for the average length life u. Give your answer...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a standard deviation of o = 40 hours. A sample of size n = 100 bulbs has an average life of 740 hours. Find the 95% confidence interval for the population mean of all bulbs produced by this firm. (use interval notation). What z value(s) did you use to calculate the confidence interval above? Explain why briefly.
1. An electric firm manufactures light bulbs that have a lifetime, X, that is approximately normally distributed with a standard deviation of 100 hours. Prior experience leads the firm to establish that the mean of X (or mean lifetime), say , follows a normal distribution with mean 140-800 hours and standard deviation σ0 10 hours. If a random sample of 25 bulbs examined turns out an average lifetime of 780 hours, solve the following. (a) Find a 95% Bayesian estinate...
An electrical firm manufactures light bulbs that have a length life with normal distribution, and a standard deviation of o = 40 hours. A sample of size n = 100 bulbs has an average life of 650 hours. Find the lower 99% confidence bound for the population mean of all bulbs produced by this firm. (use interval notation). What z value (s) did you use to calculate the confidence interval above? Explain why briefly.
An electrical firm manufactures light bulbs that have a length life with normal distribution, and mean equal to 800 hours, and a variance of 8. Find the probability that a random sample of 29 light bulbs will have a sample variance S2 between 7.81 and 16.25.
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