Question

Explain the pitfalls in the following statements.

a. People who play golf are more likely to own a luxury car than people who do not play golf. Therefore, owning a luxury car causes people to play golf.

b. Oscar Johansson noted that when he buys new shares of a company’s stock listed on Nasdaq Stockholm, the stock price usually increases if he takes a shower after making his decision. Last night, Oscar bought some shares of a company and went home to take a shower and, as he had expected, the stock price increased. Obviously, the stock price increased because Oscar  took a shower.

c. Cindy’s mother found that sending her to tutorial classes for math resulted in a 20 percent improvement in her scores. Based on this success, her mother decided to spend money to send Cindy to tutorial classes for all subjects so that Cindy’s academic performance would improve in all.

Answer 1

(a)

This statement confuses correlation and causation. There is most likely a correlation between people who own a luxury car and also play golf, since both are indicators of wealth and a luxurious lifestyle, but owning a car is not the cause of people playing golf. 

 

(b)

This statement is an example of the post hoc fallacy. Just because Oscar took a shower after buying new shares of a company’s stock and the stock price increased, this does not mean that Oscar showering caused the stock price to increase. 

 

(c)

This statement is an example of the fallacy of composition, which is the erroneous belief that what is true for a part is necessarily true for the whole. Requiring Cindy to attend tutorial classes for all subjects would waste resources on those subjects that Cindy is already good at, and would not be a good use of her time.