Question 1

A supplier of silicone sheets for producers of computer chips wants to evaluate her manufacturing process. She takes samples of size 5 from each day's output and counts the number of blemishes on each silicone sheet for 20 days consecutive days. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

A c-chart is a control chart used to monitor the count of defects per unit of output. In this case, the supplier is counting the number of blemishes on each silicone sheet, which makes the c-chart the most appropriate analysis to perform. Autoregressive modeling, exponential smoothing, and multiple linear regression are not appropriate for monitoring counts of defects.

Question 2

A contractor wants to forecast the number of contracts in future quarters, using quarterly data on number of contracts during the 10-year period from 1997 to 2006. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

To forecast the number of contracts in future quarters, the most appropriate analysis would be least-squares forecasting with monthly or quarterly data. Autoregressive modeling is used to forecast time series data, but it requires a specific type of correlation structure which may not be present in the data. One-way ANOVA and two-way ANOVA are used to analyze the differences between groups or factors, and are not appropriate for forecasting time series data. Therefore, the most suitable approach would be forecasting using historical data through using least-squares regression.

Question 3

A political pollster randomly selects a sample of 100 voters each day for 8 successive days and asks how many will vote for the incumbent. The pollster wishes to see if the percentage favoring the incumbent candidate is too erratic. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

The pollster is interested in determining if the percentage of voters favoring the incumbent candidate is too erratic. The appropriate analysis in this case is to construct a p-chart, which is a control chart used to monitor the proportion of defective items in a sample. In this case, the proportion of voters favoring the incumbent candidate is being monitored over time. A p-chart will help determine if the proportion is within control limits or if there are any unusual patterns or trends in the data. Multiple linear regression and Levene's test are not appropriate for this scenario, and exponential smoothing is not applicable since there is no time series data being analyzed.

Question 4

A Paso Robles wine producer wanted to forecast the cases of merlot wine sold. The number of cases of merlot wine sold in a 28-year period was collected. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

Exponential smoothing modeling is appropriate for forecasting time series data, such as the number of cases of wine sold over a period of time.

Question 5

A Paso Robles wine producer wanted to forecast the cases of merlot wine sold. The number of cases of merlot wine sold in a 28-year period was collected. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

Moving averages modeling is appropriate for time series data, such as the number of cases of wine sold over a period, to identify trends and forecast future values.

Question 6

An investor wanted to forecast the price of a certain stock. He collected the average daily price for the stock over the past 10 years. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

Autoregressive modeling is suitable for time series data like stock prices, as it uses past values to predict future values.

Question 7

The superintendent of a school district wanted to predict the percentage of students passing a sixth-grade proficiency test. She obtained the data on percentage of students passing the proficiency test (% Passing), daily average of the percentage of students attending class (% Attendance), average teacher salary in dollars (Salaries), and instructional spending per pupil in dollars (Spending) of 47 schools in the state. She believed that holding everything else constant, instructional spending per pupil had a positive but decreasing impact on percentage. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

Linear regression with log transformation is appropriate when there is a suspected relationship between predictor and outcome variables that is not linear. The superintendent believes that spending has a positive but decreasing impact on percentage, which suggests a possible logarithmic relationship.

Question 8

A manager of a product sales group believes the number of sales made by an employee depends on how many years that employee has been with the company and how he/she scored on a business aptitude test. A random sample of 38 employees was selected to collect data on their number of sales, number of years with the company and scores on a business aptitude test. Which of the following would you perform to draw conclusion on the belief?

Accepted Answer

Multiple linear regression would be the best choice as it allows for the analysis of the relationship between the number of sales and two explanatory variables (years with the company and business aptitude test score).

Question 9

An economist is interested to see how consumption for an economy (in $ billions) is influenced by gross domestic product ($ billions) and aggregate price (consumer price index). Annual data from 30 years were collected. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

Since the economist is interested in how consumption is influenced by both gross domestic product and aggregate price, the appropriate analysis to perform is multiple linear regression. This will allow the economist to examine the relationship between consumption and both predictors, while accounting for their potential interaction.

Question 10

The director of admissions at a state college is interested in seeing if admissions status (admitted, waiting list, denied admission) at his college is related to the type of community (urban, rural, suburban) in which an applicant resides. Which of the following tests will be the most appropriate?

Accepted Answer

The χ² test for independence is appropriate for testing the association between two categorical variables, in this case, admissions status and type of community. The other options (two-way ANOVA tests and McNemar test) are not suitable for this situation.

Question 11

A certain type of rare gem serves as a status symbol for many of its owners. In theory, for low prices, the demand increases and it decreases as the price of the gem increases. However, experts hypothesize that when the gem is valued at very high prices, the demand increases with price due to the status owners believe they gain in obtaining the gem. Data on price and quantity sold were collected for a sample of 35 rare gems of this type. Which of the following would be the most appropriate analysis to perform?

Accepted Answer

A quadratic regression model would be the most appropriate analysis to perform because it can capture the non-linear relationship between price and demand that is hypothetically present at very high prices due to the status symbol effect. This model would allow for the examination of the relationship between price and demand and provide insight into how changes in price affect demand at different price levels.

Question 12

The director of a training program wanted to know if a one week orientation would change the perception of potential clients who would perceive the program as being good. He collected information on the number of clients who would rate the program as being good before and after the orientation. Which of the following tests will be the most appropriate?

Accepted Answer

The McNemar test is the most appropriate choice as it is used for paired data and compares the proportion of individuals with a positive outcome before and after an intervention or treatment. It is commonly used in studies where the same participants are measured twice, such as in this scenario where the same clients are assessed before and after the orientation. The other tests listed are not appropriate for this type of data or research question.

Quiz 18: Data Analysis Overview

A contractor wants to forecast the number of contracts in future quarters, using quarterly data on number of contracts during the 10-year period from 1997 to 2006. Which of the following would be the most appropriate analysis to perform?

A Paso Robles wine producer wanted to forecast the cases of merlot wine sold. The number of cases of merlot wine sold in a 28-year period was collected. Which of the following would be the most appropriate analysis to perform?

A Paso Robles wine producer wanted to forecast the cases of merlot wine sold. The number of cases of merlot wine sold in a 28-year period was collected. Which of the following would be the most appropriate analysis to perform?

An investor wanted to forecast the price of a certain stock. He collected the average daily price for the stock over the past 10 years. Which of the following would be the most appropriate analysis to perform?

An economist is interested to see how consumption for an economy (in $ billions) is influenced by gross domestic product ($ billions) and aggregate price (consumer price index) . Annual data from 30 years were collected. Which of the following would be the most appropriate analysis to perform?

The director of admissions at a state college is interested in seeing if admissions status (admitted, waiting list, denied admission) at his college is related to the type of community (urban, rural, suburban) in which an applicant resides. Which of the following tests will be the most appropriate?