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.What is the 95% confidence interval for the population mean continuous run time for the Type 3 drill?
A) (59.5, 72.1)
B) (54.1, 77.5)
C) (58.0, 73.6)
D) (59.9, 71.7)

Question

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.What is the 95% confidence interval for the population mean continuous run time for the Type 3 drill?
A) (59.5, 72.1) 
B) (54.1, 77.5) 
C) (58.0, 73.6) 
D) (59.9, 71.7)

Quizplus · Accepted Answer

The 95% confidence interval for the population mean continuous run time for the Type 3 drill is (59.5, 72.1). This is because the sample mean is 65.8 and the sample standard deviation is 6.3. The critical value for a 95% confidence interval with 10 degrees of freedom is 2.262. Therefore, the margin of error is 2.262 * 6.3 = 14.2. The confidence interval is then 65.8 +/- 14.2 = (59.5, 72.1).

Exhibit 10-3 An Engineer Collected Data from Three Different Types of Power