A local botanist believes that the town water supply contains contaminants that are killing the native plant life. She intends t
o make her case to the Board of Supervisors at the next town meeting in two months but wants to have heard data to support her case. She decides to conduct an experiment to test her theory. She begins by collecting 10 plant samples from the local park and places all 10 plants in a roped-off square area that receives ample light and will be undisturbed by park visitors. Next, she places 10 scraps of paper numbered 1 to 10 in a hat, then pulls the scraps of paper at random, numbers the plants 1 to 10 and divides them into two groups. For six weeks, she waters 5 of the plants (3, 5, 7, 9 and 10) using the town water supply and 5 of the plants (plants 1, 2, 4, 6, 8) using bottled, distilled water. During the six weeks, she asks her neighbor and fellow plant lover to keep records of leaf condition (color, texture, strength) and stem and root conditions by counting the number of yellowed spots, wilted leaves, and withered offshoots. At the end of six weeks, she asks her neighbor to evaluate the 10 plants and he reports that plants 3, 5, 9 and 10 are yellowed, withering and diseased.
a. What is the hypothesis in this situation?
b. Which group of plants is the experimental group? The control group?
c. What method did the researcher use to randomly assign the groups?
d. How was double blind procedure used?
e. What was the Independent Variable? The Dependent Variable?
f. What is the Operational Definition of the Independent Variable? The Dependent Variable?
g. What possible confounding variables might the researcher not have taken into account?
