Here are some example questions inspired by statistical data with explanations for each. Try to think about the questions, and possible explanations, before you check ours. Even if you know the answer already check our explanations anyway. If you have comments about reading our explanation, please let us know!
Case 1. Deadly tomatoes.
New Nevada Hospital conducted a survey to find unsuspected patterns among patients who died in the hospital. It showed that almost 100% of them had eaten tomatoes in their life. Can you conclude from this that tomatoes are deadly?
Case 2. Born in June? You Risk Stomach Cancer!
New Nevada Hospital collected data on patients who suffer from stomach cancer. Out of the total of 480 patients surveyed, 50 were born in June. This is 25% higher than 40, the average number of birthdays per month is this group (since 480:12 = 40). They concluded that being born in June increases your risk of stomach cancer. Right?
Case 3. Math Lovers
New Nevada Chess Magazine published an article claming that the population at large shows little interest in logical thinking. To illustrate this, they reported that it is very difficult to find people who love mathematics. They received about 1000 letters in reply to this article, 990 of them from people who love mathematics, and 10 from people who hate mathematics. Can we conclude that 99% of Americans love mathematics. If we can't, what arguments can you provide?
Case 4. Are seat belts safe?
As soon as New Nevada passed the law to make the use of the seat belt mandatory for passengers and drivers in riding cars, the number of people with injuries from car accidents arriving to New Nevada Hospital increased by 40%. Why?
Case 5. Obesity makes you smart
A company specialized in academic tests for elementary schools was hired by Princetonville Charter School in New Nevada to test the children from ages 7 to 10 on a variety of academic subjects. The company found that kids who weighed more, had on average better scores on all tests. Let's stop dieting!