15.8

a

This study is mixed exeprimental and observational.

A randomization of treatments (standard or computer based curriculum) does occur. However, the choice of which school is not randomized.

b

  • Experimental factor: Type of curriculum;

  • Levels: Standard or computer based.

  • observational factor: schools;

  • Levels: school no.1, 2 and 3

There are 6 factor-level combinations:

  • School1 +standard;
  • School 1 +computer based;
  • School2 +standard;
  • School 2 +computer based;
  • School3 +standard;
  • School 3 +computer based.

c

Completely randomized design

d

The basic unit is each of the 24-student sections

15.10

a

Mixed exeprimental and observational.

The color of paper is randomized but the nature of parking lots is just observed.

b

  • Experimental factor: Color of the paper

  • Levels: Blue, green, orange

  • observational factor: What parking lot the papers are distributed in;

  • Levels: Parking lot a, b, c, d.

There are 12 factor-level combinations:

  • Parking lot a+ Blue;
  • Parking lot b+ Blue;
  • Parking lot c+ Blue;
  • Parking lot d+ Blue;
  • Parking lot a+ Orange;
  • Parking lot b+ Orange;
  • Parking lot c+ Orange;
  • Parking lot d+ Orange;
  • Parking lot a+ Green;
  • Parking lot b+ Green;
  • Parking lot c+ Green;
  • Parking lot d+ Green;

c

Repeated measures design

d

The basic unit is the papers of the same color distributed in each of the parking lots.