Be sure to clearly state the hypotheses in thehypothesis tests and state the conclusions in terms of the problem.Use ?=.?? for all tests.
The following table presents shear strength (in kN/mm) and welddiameters (in mm) for a sample of spot welds.
Diameter Strength
4.2Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 51
4.4Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 54
4.6Â Â Â Â Â Â Â Â Â Â Â Â Â Â 69
4.8Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 81
5.0Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 75
5.2Â Â Â Â Â Â Â Â Â Â Â Â Â Â 79
5.4Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 89
5.6Â Â Â Â Â Â Â Â Â Â Â Â Â Â 101
5.8Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 98
6.0Â Â Â Â Â Â Â Â Â Â Â Â Â Â 102
1.Construct a scatterplot of strength (y) versus diameter (x).Does it appear as though a linear model is appropriate?Explain.
2.Compute the correlation coefficient between x and y.
3.Compute the least-squares line for predicting shear strengthfrom weld diameter.
4.Compute the fitted value and residual for each point. (Thiscan be done with a simple option selection in Minitab.
5.Predict the strength for a diameter of 5.5 mm.
6.Can the least-squares line be used to predict the strength fora diameter of 8 mm? If so, predict the strength. If not, explainwhy not.
7.For what diameter would you predict a strength of 95kN/mm?
8.Compute the coefficient of determination and explain what itrepresents.
9.Compute a 90% confidence interval for the mean shear strengthof welds with diameters of 5.1 mm.
10.Compute a 99% prediction interval for the shear strength ofparticular weld with diameter 5.1 mm.
11.Construct two residual plots (residuals versus the fitted yvalues and a normal probability plot of the residuals) and discusswhat they tell you about the fit of the model and whether the modelassumptions are satisfied.
Please solve using Minitab and show step
