Before accepting a large shipment of bolts, the director of an elevator construction project checks The tensile strength of a simple random sample consisting of 20 bolts. She is concerned that the bolts may be counterfeits, which bear the proper markings for this grade of bolt, but are made from inferior materials. For this application, the genuine bolts are known to have a tensile strength that is normally distributed with a mean of 1400 pounds and a standard deviation of 30 pounds. The mean tensile strength for the bolts tested is 1385 pounds. Formulate and carry out a hypothesis test, using the critical value approach and at a 3% level of significance to examine the possibility that the bolts in the shipment might not be genuine. Be sure to show all the steps of this approach i.e..i. state H0 and HA, ii. select α, select the test statistic (giving reason for your choice) and compute it, iii. get the critical value, iv .compare the test statistic, v. state your decision, and vi. explain (interpret) your conclusion dentify and interpret the p-value for the test.
- Before accepting a large shipment of bolts, the director of an elevator construction project checks
The tensile strength of a simple random sample consisting of 20 bolts. She is concerned that the bolts may be counterfeits, which bear the proper markings for this grade of bolt, but are made from inferior
materials. For this application, the genuine bolts are known to have a tensile strength that is
distributed with a mean of 1400 pounds and a standard deviation of 30 pounds. The mean tensile
strength for the bolts tested is 1385 pounds.
Formulate and carry out a hypothesis test, using the critical value approach and at a 3% level of
significance to examine the possibility that the bolts in the shipment might not be genuine. Be sure to
show all the steps of this approach i.e..i. state H0 and HA, ii. select α, select the test statistic (giving reason
for your choice) and compute it, iii. get the critical value, iv .compare the test statistic, v. state your decision,
and vi. explain (interpret) your conclusion
dentify and interpret the p-value for the test.
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