A variable is normally distributed with mean 170 and standard deviation 15. Approximately what percentage of values lie between 155 and 185?

Answer and explanation

Correct answer: D. 68%

  1. Step 1: The interval is within 1 standard deviation of the mean, which holds about 68% of the values (the 68-95-99.7 rule). Answer: 68%. Why not the others: 95%: uses the wrong standard deviation band. 50%: gives half the distribution. 99.7%: uses three standard deviations.

Practise more Calculus, algebra, series and probability.

Free questions with an explanation for every one, and full timed Stúdentspróf (Iceland) mock tests.

All Calculus, algebra, series and probability questionsTake a mock test

More Calculus, algebra, series and probability questions