SAT · Problem Solving & Data Analysis · Scatterplots, tables, and probability
Question sat-q-00164
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The question
The five values in a data set are 42, 87, 82, 43, 80. What is the mean?
- 82
- 334
- 83.5
- 66.8
Show answer & worked solution
Answer: 66.8
Worked solution. Sum the values: 334. Divide by the number of values (5): 334 / 5 = 66.8.
Why each wrong choice is wrong. A distractor returns the median (middle value), which equals the mean only by coincidence. Another divides by the wrong count.
Test-day tactic. Mean is sum over count. Don't confuse it with median (middle value) or mode (most frequent value).
About this question type
Items ask you to read a value off a scatterplot, to identify the line of best fit, to compute a probability or conditional probability from a two-way table, or to interpret a relative-frequency statement.
You will see a question shaped like this one on roughly every other official SAT form, typically at a moderate position in the section — solidly within the range that separates a 600-band student from a 700-band student. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.