Question 17.13

For Exercises 17.1 and 17.2, see pages 17-3 to 17-4; for 17.3 and 17.4, see page 17-5; for 17.5 to 17.7, see page 17-8; for 17.8 to 17.10, see page 17-11; and for 17.11 to 17.13, see page 17-14.

Question 17.13

17.13 $X^{2}$ or $z$ .

The Minitab output in Figure 17.6 does not give the value of $X^{2}$ . The column labeled “ $Z$ -Value” provides similar information.

Find the value under the heading “ $Z$ -Value” for the predictor LCONC. Verify that this value is simply the estimated coefficient divided by its standard error. This is a $z$ statistic that has approximately the standard Normal distribution if the null hypothesis (slope 0) is true.
Show that the square of $z$ is $X^{2}$ . The two-sided $P$ -value for $z$ is the same as $P$ for $X^{2}$ .

17.13

(a) $Z = 8.01$ . (b) 64.16, which agrees with the output up to rounding error.