(a) A child psychologist is interested in studying how a child’s percent of pretend play differs with sex and age (4, 8, and 12 months). There are 11 infants assigned to each cell of the experiment.

(b) Brewers malt is produced from germinating barley. A home brewer wants to determine the best conditions for germinating the barley. Thirty lots of barley seed were equally and randomly assigned to 10 germination conditions. The conditions are combinations of the week after harvest (1, 3, 6, 9, or 12 weeks) and the amount of water used in the process (4 or 8 milliliters). The percent of seeds germinating is the outcome variable.

(c) 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.

(d) A marketing experiment compares four different colors of for-sale tags at an outlet mall. Each color tag is used for one week. Shoppers are classified as impulse buyers or not through a survey instrument. The total dollar amount each of the 138 shoppers spent on sale items is recorded.