a chemist for a paint company conducted an experiment to investigate whether a new outdoor paint will last longer than the older
paint. fifty blocks made from the same wood were randomly assigned to be painted with either the new paint or the old paint. the blocks were placed into a weather-controlled room that simulated extreme weather conditions such as ice, temperature, wind, and sleet. after one month in the room, the blocks were removed, and each block was rated on texture, shine, brightness of color, and chipping. the results showed that the blocks painted with the new paint generally had higher ratings than the blocks painted with the old paint. however, an analysis of the results found that the difference in ratings was not statistically significant. what can be concluded from the experiment?
A school psychologist wants to test the effectiveness of a new method for teaching reading. She recruits 500 first-grade students in District 203 and randomly divides them into two groups. Group 1 is taught by means of the new method, while group 2 is taught via traditional methods. The same teacher is assigned to teach both groups. At the end of the year, an achievement test is administered and the results of the two groups compared. (a) What is the response variable in this experiment? (b) Think of some of the factors in the study. Which are controlled? Which factor is manipulated? (c) What are the treatments? How many treatments are there? (d) How are the factors that are not controlled or manipulated dealt with? (e) What type of experimental design is this? (f) Identify the subjects. (g) Draw a diagram similar to Figure 6 or 7 to illustrate the design.
