A company is attempting to estimate the average time that its workers spend on their breaks. Several volunteer workers recorded their breaks over the course of one week. The result was 140 sample times. This sample had a mean of 13.5 minutes and a sample standard deviation of 1.75 minutes. Assuming that this sample is representative of all of the company's workers, determine the 90% confidence interval of the mean break time of the whole company. μει

The percentage of titanium in an alloy used in aerospace castings is measured in 51 randomly selected parts. The sample standard deviation is s = 0.47. Construct a 95% two-sided confidence interval for o. Assume population is approximately normally distributed. Round your answers to 4 decimal places. Statistical Tables and Charts

Suppose you have conducted 25 measurements of a random variable (Temperature) and obtained the following data in Table 2 below: Calculate the sample mean temperature, standard deviation, and standard deviation of the means of these temperature measurements.  Estimate 95% confidence interval for true mean temperature. Determine the range within which the true mean temperature exists at a 95% confidence level based on this finite dataset

One step in the manufacture of a certain metal clamp involves the drilling of four holes. In a sample of 100 clamps, the average time needed to complete this step was 80seconds and the standard deviation was 15 seconds. a.Find a 95% confidence interval for the mean time needed to complete the step. b.Find a 99.5% confidence interval for the mean time needed to complete the step. c.What is the confidence level of the interval (78,82)? d.How many clamps must be sampled so that a 95% confidence interval specifiesthe mean to within ±1 seconds? e. How many clamps must be sampled so that a 99.5% confidence interval specifies the mean to within ±1 seconds?

Sam's Long Life 75-watt light bulbs are designed to have a life of 1,150 hours with tolerances of ±205 hours. The process that makes light bulbs has a mean of 1,040 hours, with a standard deviation of 55 hours. Compute the process capability ratio and the process capability index, and comment on the overall capability of the process. (Round answers to 2 decimal places, e.g. 2.75.)

Fill in the blanks: On a particular day a random sample of 12 tins of peas is taken from the output of a canning factory and their contents are weighed. The mean and standard deviation of the weight for the sample are 301.8 gm and 1.8 gm respectively. Find 99% confidence limits for the mean weight of peas in tins produced by the factory on the day in question. use 3 decimal places E = Lower limit? Upper limit?

A process converts lead to gold. However, the production varies due to the power of the alchemist. It is known that the process is normally distributed with a standard deviation of 2.5g. How many samples must be taken to be 90% certain that an estimate of the mean process is within 1.5g of the true but unknown mean yield?

The data shown in Table 1 are the deviations from nominal diameter for holes drilled in a carbon-fiber composite material used in aerospace manufacturing. The values reported are deviations from nominal in ten-thousandths of an inch. (a) Set up and R charts on the process. Is the process in statistical control? (b) Estimate the process standard deviation using the range method. (c) If specifications are at nominal ±100, what can you say about the capability of this process? Calculate the PCR Cp Table 1. Hole Diameter Data Sample Number X1 X2 1 2 3 4 5 6 7 8 9 10 11 12 14 15 16 17 18 19 20 -30 +50 0 -50 -10 -10 +20 -40 0 0 -30 0 +20 0 0 +70 0 +10 +40 +30 +30 +30 +10 0 +20 +50 +50 -20 +50 -60 +10 0 0 +20 +10 -20 -10 0 +20 X3 X4 X5 -30 +20 +30 +50 +40 +20 +30 +20 +30 +20 +30 0 +20 +10 +40 +10 +10 -10 +50 -10 -30 -10 +50 +40 0 +30 -10 0 +30 +30 -20 +50 +30 +10 +40 +20 0 +30 +10 +30 -20 +30 +30 +20 -20 +50 +20 +10 -40 +20 -20 -10 -10 0 -20 +10 +10 +50 0 +10

1. A sample of 169 is drawn from a certain population. This sample has a mean of 80 and a standard deviation of 10. Find the standard error of the mean.

The amount of time that a customer spends waiting at an airport check-in counter is a random variable with mean 8.0 minutes and standard deviation 1.6 minutes. Suppose that arandom sample of n = 46 customers is observed. Find the probability that the average time waiting in line for these customers is (a) Less than 10 minutes (b) Between 5 and 10 minutes (C) Less than 6 minutes Round your answers to four decimal places (eg. 0.9876). (a) The probability is i (b) The probability is i (c) The probability is Statistical Tables and Charts