A researcher conducts an experiment on a new drug for enhancing memory and the researcher concludes that the drug is effective. However, by chance alone the many participants having excellent memories were placed in the experimental group. This may lead to a:

Who is credited with the following quote: "Instead of studying a thousand rats for one hour

each, or a hundred rats for ten hours each, the investigator is likely to study one rat for a thousand hours." A) Sir Ronald A. Fisher B) Herman Ebbinghaus C) Gustav Fechner D) B. F. Skinner E) Wilhelm Wundt

Does chi-square allow a researcher to conclude that one variable causes the other?

a. no b. only when the variables are perfectly correlated c. not unless the expected frequency of one of the cells in the contingency table is <5 d. yes