A Schoolteacher Is Worried That the Concentration of Dangerous,cancer-Causing Radon

question 22

Multiple Choice

A schoolteacher is worried that the concentration of dangerous,cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L.The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L.At a 5% significance level,the decision is to ________________________________________________.

• A) reject H_o;we can conclude that the mean concentration of radon gas is greater than the safe level
• B) reject H_o;we cannot conclude that the mean concentration of radon gas is greater than the safe level
• C) not reject H_o;we can conclude that the mean concentration of radon gas is greater than the safe level
• D) not reject H_o;we cannot conclude that the mean concentration of radon gas is greater than the safe level

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Definitions:

Fixed Expenses

Regularly occurring costs that remain constant in total regardless of changes in activity within a relevant period.

Contribution Margin

The difference between a company's sales revenue and its variable costs, serving as a measure of the profitability of individual products.

Monthly Unit Sales

The total number of units of a product sold by a company in a given month, often used to track sales trends and forecast demand.

Variable Costs

Costs that vary directly with the level of production or output, such as raw materials and direct labor expenses.