Plot Number of Earthworms
Students in Mr. Smith's science class were taking random samples throughout the schoolyard for population analysis. One easy-to-locate organism that they counted was the earthworm, Lumbricus terrestris. Their data is displayed above. Several students were concerned about the count in plot C, as it was much lower than the other plots. Sandra suggested that they recount, but this time, count the earthworms over an extended period of time. Sam commented that it would skew the results in the other direction. He added that this was a random sample, and plot C was in sandy soil near the parking lot.
What comment would you make concerning the students experimental design?
A) They should omit plot C from the data and consider it as an error.
B) Sandra is correct. They should count the earthworms in plot C over an extended period of time.
C) Sam is correct. The plot selection was random and earthworms do not typically live in sandy, dry soil.
D) They should omit the idea of random selection of plots and purposely select plots I thought would be typical of earthworm habitats.