In: Statistics and Probability
When survey data indicated that a company 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 bags without tearing the inner liner of the bag. Data were collected on 19 bags and the plate gap on the bag-sealing equipment was used to predict the tear rating of a bag. The results are displayed in the accompanying table and the regression equation is the following. Complete parts (a) through (c).
ModifyingAbove Upper Y with caret Subscript iYiequals=0.79060.7906plus+0.46820.4682Xi,
with
Summation from i equals 1 to n∑i=1nYiequals=14.7414.74,
Summation from i equals 1 to n∑i=1nUpper Y Subscript i Superscript 2Y2iequals=40.320240.3202,
and
Summation from i equals 1 to n∑i=1nXiYiequals=20.1720.17.
Bag | Plate gap (X) | Tear rating (Y) |
1 | -0.3 | 0.09 |
2 | 0.3 | 0.08 |
3 | 2.1 | 0.47 |
4 | 1.5 | 0.82 |
5 | 0 | 0.32 |
6 | -0.3 | 0.36 |
7 | -0.3 | 0.78 |
8 | -0.3 | 1.93 |
9 | 0 | 0.23 |
10 | -1.5 | 0.13 |
11 | -1.5 | 0.12 |
12 | 2.4 | 3.96 |
13 | -2.1 | 0.04 |
14 | 0 | 0.56 |
15 | -3 | 0.01 |
16 | -2.1 | 0.05 |
17 | 2.1 | 0.43 |
18 | 2.1 | 4.31 |
19 | 0.3 | 0.05 |
a. Determine the coefficient of determination, r2,and interpret its meaning.
What is the meaning of the coefficient ofdetermination? (Choose Below)
A. It measures the variability in the actual plate gap from the predicted plate gap.
B. It measures the variability in the actual tear rating from the predicted tear rating.
C. It is the proportion of the variation in the plate gap that is explained by the variability in the tear rating.
D. It is the proportion of the variation in the tear rating that is explained by the variability in the plate gap.
b. Determine the standard error of the estimate.
SYX = ___? (Round to four decimal places asneeded.)
c. How useful do you think this regression model is for predicting the tear rating based on the plate gap in thebag-sealing equipment? (Choose Below)
What is the meaning of the coefficient ofdetermination? (Choose Below)
A. It measures the variability in the actual plate gap from the predicted plate gap.
B. It measures the variability in the actual tear rating from the predicted tear rating.
C. It is the proportion of the variation in the plate gap that is explained by the variability in the tear rating.
D. It is the proportion of the variation in the tear rating that is explained by the variability in the plate gap.
b. Determine the standard error of the estimate.
SYX = ___? (Round to four decimal places asneeded.)
c. How useful do you think this regression model is for predicting the tear rating based on the plate gap in thebag-sealing equipment? (Choose Below)
Excel > Data > Data Anlysis > Regression
SUMMARY OUTPUT | ||||||||
Regression Statistics | ||||||||
Multiple R | 0.5783542 | |||||||
R Square | 0.33449358 | |||||||
Adjusted R Square | 0.295346144 | |||||||
Standard Error | 1.063379601 | |||||||
Observations | 19 | |||||||
ANOVA | ||||||||
df | SS | MS | F | Significance F | ||||
Regression | 1 | 9.661868187 | 9.661868187 | 8.54445681 | 0.009486453 | |||
Residual | 17 | 19.22319497 | 1.130776175 | |||||
Total | 18 | 28.88506316 | ||||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Lower 95.0% | Upper 95.0% | |
Intercept | 0.790573823 | 0.244008436 | 3.239944641 | 0.004815081 | 0.275761025 | 1.305386622 | 0.275761025 | 1.305386622 |
Plate gap (X) | 0.468171072 | 0.160163056 | 2.923090284 | 0.009486453 | 0.130256562 | 0.806085583 | 0.130256562 | 0.806085583 |
a)
the coefficient of determination, r2 = 0.3345
It is the proportion of the variation in the tear rating that is explained by the variability in the plate
33.45% of the variation in the tear rating that is explained by the variability in the plate
b)
Standard error of the estimate, Se = 1.0634
c)
r^2 is nearer to 0.5 and Standard error is relatively large, so the model is fairly useful for predicting tear rating