Managers at an automobile manufacturing plant would like to es mean completion time of an assembly line operation, . The mar to choose a random sample of completion times and estimate u sample. Assuming that the standard deviation of the population completion times is 10.1 minutes, what is the minimum sample si: for the managers to be 95% confident that their estimate is withir of u? Carry your intermediate computations to at least three decimal Write your answer as a whole number (and make sure that it is

A study conducted by Hershey's discovered that Americans consumed an average of 11.4 pounds of chocolate per year. Let's assume that the annual chocolate consumption follows the Normal distribution with mean 11.4 pounds and a standard deviation of 3.6 pounds. Answer the following questions, performing all computations with Excel functions.

Rachael got a 660 on the analytical portion of the Graduate Record Exam (GRE). If GRE scores are normally distributed and have mean μ = 600 and standard deviation σ = 30, what is her standardized score?

Use the formula to find the standard error of the distribution of differences in sample means, x⎯⎯1−x⎯⎯2x¯1-x¯2.Samples of size 40 from Population 1 with mean 3.7 and standard deviation 1.9 and samples of size 40 from Population 2 with mean 1.9 and standard deviation 1.2Round your answer for the standard error to two decimal places.standard error = Enter your answer in accordance to the question statement

Assume that the readings at freezing on a bundle of thermometers are normally distributed with a mean of 0°C and a standard deviation of 1.00°C. A single thermometer is randomly selected and tested. Find Pg9, the 69-percentile. This is the temperature reading separating the bottom 69% from the top 31%. P69 = °C

Suppose that a category of world class runners are known to run a marathon (26 miles) in an average of 146 minutes with a standard deviation of 13minutes. Consider 49 of the races.Let X = the average of the 49 races. Find the 60th percentile for the average of these 49 marathons. (Round your answer to two decimal places.)min

Assume that the distribution of scores on a college entrance exam is normally distributed with a mean of 490 and a standard deviation of 43. For each score in the table below, convert the raw score into a corresponding z-score. original score Z-score 621 398 586 710

Assume that adults have IQ scores that are normally distributed with a mean of 96 and a standard deviation 19.3. Find the first quartile Q1,which is the IQ score separating the bottom 25% from the top 75%. The first quartile is?