Question

For 10 weeks Dolly wrote down everything she ate as well as weighed herself each morning. For two separate weeks during the 10 week period when her car was broken down and she was walking to work she was running late each day so she did not have a chance to write down what she ate.

At the end of the 10 weeks she graphed her weight over time and noticed that for the two weeks she didn't write down anything she lost weight. She concluded that for this experiment NOT writing down what she ate would help her lose weight.

Which mistake did Dolly have in her conclusion?
Responses
A Confusing causation with correlation.Confusing causation with correlation.
B Confusing an experiment with an observational study.Confusing an experiment with an observational study.
C That her experiment lasted for 10 weeks since she did not record what she ate for 2 weeks.That her experiment lasted for 10 weeks since she did not record what she ate for 2 weeks.
D She did not make any mistakes in her conclusion.

Answer 1

A. Confusing causation with correlation.

Dolly observed weight loss during the weeks she didn't record food, but that coincided with increased walking to work. The lack of recording is correlated with weight loss, not necessarily the cause — the increased exercise (and other unrecorded changes) is a plausible confounder.