For Exercises 15.1 to 15.3, see pages 15-6 to 15-7; for 15.4 to 15.6, see page 15-10; for 15.7, see pages 15-12 to 15-13; for 15.8 to 15.10, see page 15-15; for 15.11, see page 15-16; for 15.12 and 15.13, see page 15-18; and for 15.14 to 15.16, see pages 15-20 to 15-21.

Question 15.19

15.19 Describe the design.

Each of the following situations is a two-way study design. For each case, identify the response variable and both factors, and state the number of levels for each factor ( and ) and the total number of observations .

  1. A video game developer wants to see if haptic feedback (forces and vibrations applied through a joystick) enhances a player’s excitement level. He considers two types of games (racing and shooter) and four different levels of haptic feedback (none, force only, vibration only, and force and vibration). He plans to assign five players to each combination. A wrist band will monitor the player’s skin temperature.
  2. A restaurant chain is interested in whether calorie-posted menus lead to lower-calorie choices. Two hundred participants were recruited on Amazon Mechanical Turk and asked to order their lunch. Each participant was presented an identical food item menu but the menu varied in terms of type (traditional, calories also posted, and calories posted with food items organized by calories) and price pattern (prices positively or negatively correlated with calories). The total calories of the lunch ordered was recorded.
  3. The strength of concrete depends upon the formula used to prepare it. An experiment compares six different mixtures. Nine specimens of concrete are poured from each mixture. Three of these specimens are subjected to 0 cycles of freezing and thawing, three are subjected to 100 cycles, and three are subjected to 500 cycles. The strength of each specimen is then measured.

15.19

(a) Response: skin temperature. Factors: haptic feedback (4 levels) and type of game (2 levels). . (b) Response: total calories. Factors: menu type (3 levels) and price pattern (2 levels). . (c) Response: strength. Factors: mixture (6 levels) and cycles of freezing (3 levels). .