TABLE 12-5 A Corporation Randomly Selects 150 Salespeople and Finds That 66

question 145

Multiple Choice

TABLE 12-5
A corporation randomly selects 150 salespeople and finds that 66% who have never taken a self-improvement course would like such a course. The firm did a similar study 10 years ago in which 60% of a random sample of 160 salespeople wanted a self-improvement course. The groups are assumed to be independent random samples. Let π₁ and π₂ represent the true proportion of workers who would like to attend a self-improvement course in the recent study and the past study, respectively.
-Referring to Table 12-5, the company tests to determine at the 0.05 level whether the population proportion has changed from the previous study. Which of the following is most correct?

• A) Reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has changed over the intervening 10 years.
• B) Do not reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has not changed over the intervening 10 years.
• C) Reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has increased over the intervening 10 years.
• D) Do not reject the null hypothesis and conclude that the proportion of employees who are interested in a self-improvement course has increased over the intervening 10 years.

Estimate population parameters from sample statistics.

Understand the implications of sampling bias and how it affects statistical inference.

Understand the concept of margin of error and how it affects the precision of confidence intervals.

Apply statistical methods to practical problems in quality control and research.

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Definitions:

Variable Costing

An accounting method that only includes variable production costs (materials, labor, and overhead) in product cost calculations, excluding fixed costs.

Operating Income

Profit generated from a company's regular business operations, excluding expenses like taxes and interest.

Contribution Margin

The amount of revenue remaining after deducting variable costs, which can be used to cover fixed costs and contribute to profit.

Fixed Costs

Expenses that do not change with the level of output or sales over a short period, such as rent, salaries, and insurance.