An environmental scientist identified a point source for E. Coli at the edge of a stream. She then measured y = E. Coli, in colony forming units per 100 ml of water, at different distances, in feet, downstream from the point source. Suppose she obtains the following pairs of (x, y ).

(a) Transform the x values to x€² = log10x and plot the scatter diagram of y versus x€².
(b) Fit a straight line regression to the transformed data.
(c) Obtain a 90% confidence interval for the slope of the regression line.
(d) Estimate the expected y value corresponding to x = 300 and give a 95% confidence interval.

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