- An Electrical Firm Manufactures Light Bulbs That Have A Length Of Life That Is Approximately Normally Distributed With A 1 (17.88 KiB) Viewed 25 times
- An Electrical Firm Manufactures Light Bulbs That Have A Length Of Life That Is Approximately Normally Distributed With A 2 (19.45 KiB) Viewed 25 times
An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 45 hours. How large a sample is needed if we wish to be 98% confident that our sample mean will be within 8 hours of the true mean? Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. The required sample size is (Round up to the nearest whole number as needed.) (...)
A UCLA researcher claims that the life span of mice can be extended by as much as 25% when the calories in their diet are reduced by approximately 40% from the time they are weaned. The restricted diet is enriched to normal levels by vitamins and protein. Assuming that it is known from previous studies that o=6.4 months, how many mice should be included in the sample if we wish to be 99% confident that the mean life span of the sample will be within 3 months of the population mean for all mice subjected to this reduced diet? Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. The required sample size is. (Round up to the nearest whole number as needed.) C