Correction for Exercise 12-19. The answer given in the manual referred to a slightly different question in the previous edition.

12.19  Linear and quadratic trend in Conti and Musty (1984) using the log transformed data from Table 11.5.

The results given below assume that you have added the three observations mentioned in the exercise.

 

Group:

Control

0.1

0.5

1

2

 

Means

1.981

2.318

2.557

2.353

2.124

 

Linear

  -0.72

  -0.62

-0.22

    0.28

  1.28

Saj2 = 2.668

Quadratic

  0.389

  0.199

-0.362

-0.612

0.387

Sbj2 = 0.846

 

There is a significant quadratic trend, but no significant linear trend. This quadratic trend is quite visible in the means.

Source

df

   SS

MS

F

Treatments

4

 1.963

0.491

8.103*

 

Linear

1

    0.0088

0.0088

0.145

 

Quadratic

1

    1.1490

1.1487

18.987*

Error

45

2.726

0.0605

 

Total

49

4.689