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 nine times...

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 nine times to a girder, are shown in the following table. We wish to determine whether there is any difference between the two methods. Assume the same standard deviations. (Note that we will perform
   unpaired
   comparison. We
   do not
   perform a paired test.)

1.2. For a sample standard deviation, use Excel function STDEV.S(), not STDEV.P(). Fill in the blanks below:

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

1.4.  Find a 90% confidence interval on the mean difference between the two methods and use it to answer the question in
1.3.