A chemical engineer found that by adding different amounts of an additive to gasoline, she could reduce the amount of nitrous oxides (NOx) coming from an automobile engine. A specified amount was added to a gallon of gas and the total amount of NOx in the exhaust collected. Suppose, in suitable units, the data are

(a) Obtain the least squares fit, of a straight line, to the amount of NOx.

(b) Test whether or not the slope \(\beta=0\). Take \(\alpha=\) 0.10 as your level of significance.

(c) Give a 99% confidence interval for the mean value of NOx when the amount of additive is 9 .

(d) What additional danger is there when using your estimate in part (c)?

Transcribed Image Text:

Amount of additive 1 2345 NOx 19 17 14 13 12