Exhibit 9-4

question 53

Multiple Choice

Exhibit 9-4.A school teacher 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. Refer to Exhibit 9-4.At a 5% significance level,the critical value(s) is (are) _______.

• A)-1.690
• B)1.690
• C)-1.96 and 1.96
• D)-2.030 and 2.030

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Definitions:

Median

A measure of central tendency in statistics that represents the middle value in a sorted list of numbers.

Standard Deviation

A numerical indicator that calculates the degree of spread or variability among a series of data points.

Mean

A statistical measure defined as the sum of all values in a data set divided by the number of values, representing the average.

Median

The middle value in a sorted list of numbers, effectively dividing the dataset into two equal halves.