In a manufacturing process, the assembly line speed (feet per minute) is believed to affect the number of defective parts found during the inspection process. Data (File 3) are collected on the number of defective parts for a variety of line speeds. Develop a linear regression equation that can be used to predict the number of defective parts given the line speed. Line Speed Number of Defective Parts Found
20 21
20 19
40 15
30 16
60 14
40 17

Required:
a. Develop a scatter chart with line speed as the independent variable. What does the chart indicate about the relationship between line speed and the number of defective parts found?
b. Use the data to develop an estimated regression equation that could be used to predict the number of defective parts found, given the line speed. What is the estimated regression model?
c. Test whether each of the regression parameters βo and β1 is equal to zero at 0.01 level of significance. What are the correct interpretations of the estimated regression parameters?
d. How much of the variation in the number of defective parts found for the sample data does the model you estimated in part (b) explain?