Question

An article described an investigation into the coating weights for large pipes resulting from a galvanized coating process. Production standards call for a true average weight of 200 lb per pipe. The accompanying descriptive summary and boxplot are from Minitab. Variable N Mean Median TrMean StDev SEMean ctg wt 30 206.66 206.00 206.81 6.35 1.16 Variable Min Max Q1 Q3 ctg wt 193.00 218.00 202.75 212.00 Coating weight 190 200 210 220 (a) What does the boxplot suggest about the status of the specification for true average coating weight? It appears that the true average weight could be significantly off from the production specification of 200 lb per pipe. It appears that the true average weight is not significantly different from the production specification of 200 lb per pipe. It appears that the true average weight is approximately 202 lb per pipe. It appears that the true average weight is approximately 218 lb per pipe. (b) A normal probability plot of the data was quite straight. Use the descriptive output to test the appropriate hypotheses. (Use ? = 0.05.) State the appropriate hypotheses. H0: ? = 200 Ha: ? ? 200 H0: ? = 200 Ha: ? > 200 H0: ? = 200 Ha: ? < 200 H0: ? ? 200 Ha: ? = 200 Calculate the test statistic and determine the P-value. (Round your test statistic to two decimal places and your P-value to three decimal places.) t = P-value = What can you conclude? Reject the null hypothesis. There is sufficient evidence to conclude that the true average weight differs from 200 lb per pipe. Do not reject the null hypothesis. There is sufficient evidence to conclude that the true average weight differs from 200 lb per pipe. Reject the null hypothesis. There is not sufficient evidence to conclude that the true average weight differs from 200 lb per pipe. Do not reject the null hypothesis. There is not sufficient evidence to conclude that the true average weight differs from 200 lb per pipe. You may need to use the appropriate table in the Appendix of Tables to answer this question.

An article described an investigation into the coating weights for large pipes resulting from a galvanized coating process. Production standards call for a true average weight of 200 lb per pipe. The accompanying descriptive summary and boxplot are from Minitab.
Variable N Mean Median TrMean StDev SEMean
ctg wt 30 206.66 206.00 206.81 6.35 1.16
Variable Min Max Q1 Q3
ctg wt 193.00 218.00 202.75 212.00
Coating weight
190 200 210 220
(a) What does the boxplot suggest about the status of the specification for true average coating weight?
It appears that the true average weight could be significantly off from the production specification of 200 lb per pipe.
It appears that the true average weight is not significantly different from the production specification of 200 lb per pipe.
It appears that the true average weight is approximately 202 lb per pipe.
It appears that the true average weight is approximately 218 lb per pipe.
(b) A normal probability plot of the data was quite straight. Use the descriptive output to test the appropriate hypotheses. (Use ? = 0.05.)
State the appropriate hypotheses.
H0: ? = 200
Ha: ? ? 200
H0: ? = 200
Ha: ? > 200
H0: ? = 200
Ha: ? < 200
H0: ? ? 200
Ha: ? = 200
Calculate the test statistic and determine the P-value. (Round your test statistic to two decimal places and your P-value to three decimal places.)
t =
P-value =
What can you conclude?
Reject the null hypothesis. There is sufficient evidence to conclude that the true average weight differs from 200 lb per pipe.
Do not reject the null hypothesis. There is sufficient evidence to conclude that the true average weight differs from 200 lb per pipe.
Reject the null hypothesis. There is not sufficient evidence to conclude that the true average weight differs from 200 lb per pipe.
Do not reject the null hypothesis. There is not sufficient evidence to conclude that the true average weight differs from 200 lb per pipe.
You may need to use the appropriate table in the Appendix of Tables to answer this question.

Added by Christopher J.

Question

Please give Ace some feedback