Let x = boiler steam pressure in 100 lb/in² and let y = critical sheer strength of boiler plate steel joints in tons/in2. We have the following data for a series of factory boilers.

(a) Make the logarithmic transformations x' = log x and y' = log y. Then make a scatter plot of the 1xoe, yoe2 values. Does a linear equation seem to be a good ­t to this plot?

(b) Use the (x’, y’) data points and a calculator with regression keys to ­fund the least-squares equation y’ = a + bx’. What is the sample correlation coeffi­cient?

(c) Use the results of part (b) to fi­nd estimates for a and b in the power law y = ax^β. Write the power law giving the relationship between time and Amp buildup.

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