Posted: February 16th, 2020
Regression Assignment
12.3 Fitting a straight line to a set of data yields the following
prediction line:
Yn
i = 16 – 0.5Xi
a. Interpret the meaning of the Y intercept, b0.
b. Interpret the meaning of the slope, b1.
c. Predict the value of Y for X = 6.
Starbucks Coffee Co. uses a data-based approach to improving
the quality and customer satisfaction of its products.
When survey data indicated that Starbucks needed to improve its
package-sealing process, an experiment was conducted to determine
the factors in the bag-sealing equipment that might be affecting
the ease of opening the bag without tearing the inner liner
of the bag. (Data extracted from L. Johnson and S. Burrows, “For
Starbucks, It’s in the Bag,” Quality Progress, March 2011,
pp. 17–23.) One factor that could affect the rating of the ability of
the bag to resist tears was the plate gap on the bag-sealing equipment.
Data were collected on 19 bags in which the plate gap was
varied. The results are stored in Starbucks.
a. Construct a scatter plot.
b. Assuming a linear relationship, use the least-squares method to
determine the regression coefficients b0 and b1.
c. Interpret the meaning of the slope, b1, in this problem.
d. Predict the mean tear rating when the plate gap is equal to 0.
e. What should you tell the management of Starbucks about the relationship
between the plate gap and the tear rating?
