A variable has a normal distribution. Approximately what proportion of values lie within two standard deviations of the mean?

Answer and explanation

Correct answer: C. About

  1. Step 1: Recall the rule for normal distributions: roughly , and lie within one, two and three standard deviations. Step 2. Two standard deviations corresponds to about . **Answer: about . Why not the others:** and belong to one and three standard deviations, and is the share on one side of the mean.

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