Exam 10: Statistical Thinking And Applications

A manager at a market research firm randomly sampled 254 adult residents of Ohio and asked each resident if he/she planned to vacation outside of Ohio this coming summer.Sixty-three of these adults responded that they plan to vacation outside of Ohio this coming summer.What is the 95% confidence interval for the population proportion of adult residents of Ohio who plan to vacation outside of Ohio this coming summer?

Historical production data indicate that the diameter of a ball bearing is normally distributed with a mean of 0.525 cm and a standard deviation of 0.008 cm.Suppose that a sample of 16 ball bearings are randomly selected from a very large lot.Determine the probability that the average diameter of a sampled ball bearing is greater than 0.530 cm.

_____ sampling is based on the assumption that if the first element is chosen at random,the entire sample will have the properties of a simple random sample.

When interactions are present in an experiment,main effects have little meaning.

What are the advantages of studying a sample from the population instead of the studying the entire population though a census?

A _____ can take on any real value over a specified interval of real numbers.

A process engineer at POC Electronics is trying to determine relationships between two chemicals and a certain material used in the cleaning of a manufactured resistor.Specifically,the resistor can be cleaned using two levels of Chemical A,two levels of Chemical B,and either Type A or B of a cleaning material.Below are the results of the experiment run by the process engineer.Determine the main effects for this experiment.

At the organizational level,statistics helps executives with all of the following EXCEPT:

A firm is planning to conduct a study on the quality dimensions of its products and wants to determine the sample size required to estimate the process mean with a sampling error of at most 0.1 at a 90 percentage confidence level.The standard deviation of the process was found to be 0.67.Determine the sample size.

Which of the following is NOT a type of sampling procedure?

Special causes of variation are often called _____ causes of variation.

A discrete random variable can take on only finite values.

A(n)_____ experiment is a test or series of tests that enables the experimenter to compare two or more methods to determine which is better or determine levels of controllable factors to optimize the yield of a process or minimize the variability of a response variable.

Exhibit 10-2 A manager of a hotel chain is interested in investigating whether there is a relationship between staff labor hours and bed-day occupancy incurred by a hotel in a month.The manager randomly selected 17 of the hotels in the chain across the country and recorded, for each of the hotels, the staff's total labor hours for the month of July and the number of bed-days of occupancy for that month. (A hotel has occupied one "bed-day" if one bed is occupied (rented)for an entire day.)The manager is interested in seeing if the labor hours incurred can be predicted from the number of bed-days of occupancy on a monthly basis. The sample data were analyzed using Excel.Shown below is part of the regression analysis output. -Refer to Exhibit 10-2.According to this regression analysis,what percentage of the variation in the number of monthly labor hours required for a hotel can be explained by the number of bed-day of occupancy in a month?

Products are boxed in groups of 25.Drawing a sample of boxes and inspecting all units in the boxes selected is an example of systematic sampling.

A sample of size sixteen is randomly selected from a population of size 90.Determine the standard error of the mean if the population standard deviation equals 20.

A government report gives a 99% confidence interval for the proportion of welfare recipients who have been receiving welfare benefits for more than 5 years to be 21% ± 4.5%.Which of the following intervals could not be a 95% confidence interval for the proportion of welfare recipients who have been receiving welfare benefits for more than 5 years?

Understanding processes provides the context for determining the effects of ____ and the proper type of managerial action to be taken.

A mathematical function that assigns numerical values to every possible outcome in a sample space is called a _____.

Exhibit 10-3 An engineer collected data from three different types of power drills.Specifically, the engineer collected data on how long (in minutes)each type of drill would run continuously after a full battery recharge.Each drill was charged and run continuously 15 times.The reported data are contained in the following table.The engineer analyzed the data using one-way ANOVA in Excel and the results from Excel are also given below. -Refer to Exhibit 10-3.The one-way ANOVA was used to determine if the population mean continuous run times are equal (the null hypothesis)for all three types of drills,or if all pairs of population means are not equal (the alternative hypothesis).Which decisions could the manager make?