Que 1

An article shows data to compare several methods for predicting the shear strength for steel plate girders. Data for two of these methods, the Karlsruhe and Lehigh procedures, when applied thirteen times to a girder, are shown in the following table.

Karlsruhe Method	Lehigh Method
1.291894	1.191559
1.133866	1.03033
1.208227	1.175972
1.198896	1.109854
1.220118	1.225096
1.196164	1.133288
1.229591	1.250246
1.270881	1.281777
1.193054	1.208047
1.198849	1.101918
1.204478	1.197777
1.218514	1.12562
1.288960	1.293725

We wish to determine whether there is any difference between the two methods. We do not know the population standard deviations (and do perform a t-test). ?However, we assume the population standard deviations are same. (Note that we will perform unpaired comparison. We do not perform a paired test.)

Part (a) Do the data suggest that the two methods provide the same mean shear strength? Use alpha =0.1. ?Find the P-value rounded to 6 ?decimal places (using Microsoft Excel.)

Part (b) State the appropriate conclusion.

Part (c) ?Find a 90% ?confidence interval on the mean difference between the two methods?