CNN News Clip

"I signed up for Hunter in History 17," said Ben. "Why did you sign up for her?" asked Ted. "Don't you know she has given only three A's in the last 14 years?!" "That's just a rumor. Hunter grades on a curve," Ben replied. "Don't give me that `on a curve' stuff," continued Ted; "I'll bet you don't even know what that means. Anyway, my sister-in-law had her last year and said it was so bad that ."

In this section, Ted and Ben will learn what it means to grade on a curve. Many everyday examples can be represented by bell-shaped, or normal, curves. Ted and Ben will see how to make certain predictions based on this normal distribution. On the other hand, some data are said to be "skewed," which means that they deviate from a normal distribution. For example, the CNN clip at the left shows data which indicate that going to movies is very "age skewed" toward the 18- to 29-year-old age group.