Question

Be sure to clearly state your hypotheses in the hypothesis tests and state your conclusions in terms of the problem. Use ?=.?? for all tests.

The following table presents shear strength (in kN/mm) and weld diameters (in mm) for a sample of spot welds.

Diameter Strength

4.2                51

4.4                54

4.6               69

4.8                81

5.0                75

5.2               79

5.4                89

5.6               101

5.8                98

6.0               102

6.Can the least-squares line be used to predict the strength for a diameter of 8 mm? If so, predict the strength. If not, explain why not.

7.For what diameter would you predict a strength of 95 kN/mm?

8.Compute the coefficient of determination and explain what it represents.

9.Compute a 90% confidence interval for the mean shear strength of welds with diameters of 5.1 mm.

10.Compute a 99% prediction interval for the shear strength of particular weld with diameter 5.1 mm.

11.Construct two residual plots (residuals versus the fitted y values and a normal probability plot of the residuals) and discuss what they tell you about the fit of the model and whether the model assumptions are satisfied.

Please solve using Minitab and show step

Answer 1