Does ice cream prevent flu? Statistical studies show that a negative correlation exists between the number of flu cases reported each week throughout the year and the amount of ice cream sold in that particular week. Based on these findings, should physicians prescribe ice cream to patients who have colds and flu or could this conclusion be based on erroneous data and statistically unjustified?

a. Discuss at least one lurking variable that could affect these results.

b. Explain how multiple causes could affect whether an individual catches flu.