In: Statistics and Probability
The effect of sealer plate temperature (X1) and sealer plate clearance (X2) in a soap wrapping machine affects the percentage of wrapped bars (Y) which pass inspection. Obtain the residuals and draw a box plot of the residuals. Also prepare a normal probability plot. Interpret the plots and summarize your findings.
X1   X2   Y
190   130   35
176   174   81.7
205   134   42.5
210   191   98.3
230   165   52.7
192   194   82
220   143   34.5
235   186   95.4
240   139   56.7
230   188   84.4
200   175   94.3
218   156   44.3
220   190   83.3
210   178   91.4
208   132   43.5
225   148   51.7
Analysis:

the box plot indicates that there are no outliers for the residuals. tHE range of residuals is (15--15) = 30. The median value is one indicating that 50% of the residuals are less than 1

An S shape is formed in the normal probability plot. This indicates that the assumption of normality of residuals is followed.
process:
data -> Data Analytics -> regression
dependent variable -> Y
independent variables -> X1 and X2
output:
| SUMMARY OUTPUT | ||||||||
| Regression Statistics | ||||||||
| Multiple R | 0.897984626 | |||||||
| R Square | 0.806376388 | |||||||
| Adjusted R Square | 0.77658814 | |||||||
| Standard Error | 11.20467409 | |||||||
| Observations | 16 | |||||||
| ANOVA | ||||||||
| df | SS | MS | F | Significance F | ||||
| Regression | 2 | 6797.063 | 3398.531 | 27.07029 | 2.32E-05 | |||
| Residual | 13 | 1632.081 | 125.5447 | |||||
| Total | 15 | 8429.144 | ||||||
| Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Lower 95.0% | Upper 95.0% | |
| Intercept | -67.8843597 | 40.58652 | -1.67258 | 0.118289 | -155.566 | 19.79749 | -155.566 | 19.79749 | 
| X1 | -0.064189113 | 0.163914 | -0.3916 | 0.701696 | -0.4183 | 0.289926 | -0.4183 | 0.289926 | 
| X2 | 0.906088617 | 0.123371 | 7.344429 | 5.63E-06 | 0.639562 | 1.172615 | 0.639562 | 1.172615 | 
| RESIDUAL OUTPUT | ||
| Observation | Predicted Y | Residuals | 
| 1 | 37.71122898 | -2.71123 | 
| 2 | 78.47777573 | 3.222224 | 
| 3 | 40.37274675 | 2.127253 | 
| 4 | 91.69885237 | 6.601148 | 
| 5 | 66.85676605 | -14.1568 | 
| 6 | 95.57252226 | -13.5725 | 
| 7 | 47.5647076 | -13.0647 | 
| 8 | 85.56368144 | 9.836319 | 
| 9 | 42.65657086 | 14.04343 | 
| 10 | 87.69680424 | -3.2968 | 
| 11 | 77.84332562 | 16.45667 | 
| 12 | 59.47223785 | -15.1722 | 
| 13 | 90.15087261 | -6.85087 | 
| 14 | 79.91970034 | 11.4803 | 
| 15 | 38.36800217 | 5.131998 | 
| 16 | 51.77420512 | -0.07421 |