SAT Math Multiple Choice Question 859: Answer and Explanation
4. Many people shop online primarily because they get access to product ratings submittedby fellow shoppers. The frequency table above gives the most recent 20 customer ratingsfor a certain product sold online. What is the mean rating for this product?
- A. 3.6
- B. 3.8
- C. 4
- D. 5
Correct Answer: A
Category: Problem Solving and Data Analysis / Statistics and Probability
Strategic Advice: To find the mean of a data set presented in a frequency table, multiply each data value (here, the rating) by the number of times it occurs (the frequency). Then, add the results and divide by the total number of data values.
Getting to the Answer: The mean rating means the average score given. The sum of the ratings is: (1 × 1) + (2 × 3) + (3 × 5) + (4 × 5) + (5 × 6) = 1 + 6 + 15 + 20 + 30 = 72. Divide by the total number of ratings (20) to find that the mean is 72 ÷ 20 = 3.6, which is (A).