alleryStart learning →In a sample of 100 cars the number of faulty cars has a mean of 10 and a standard deviation of 3. About 68 percent of samples hold how many faulty cars?
ABetween 4 and 16
BBetween 1 and 19
CBetween 9 and 11
DBetween 7 and 13
Answer & Solution
Correct answer: D. Between 7 and 13
1. About 68 percent of values lie within one standard deviation of the mean.
2. One standard deviation here is 3.
3. Stepping down from 10 gives 10 minus 3, which is 7.
4. Stepping up from 10 gives 10 plus 3, which is 13.
5. The range 4 to 16 is two standard deviations wide and covers about 95 percent instead.
_Source: OpenStax High School Statistics (CC BY 4.0), section 6.1 The Standard Normal Distribution_
Keep practising The Normal Distribution
Browse all The Normal Distribution questions for Praxis Core (Teaching), or explore more Mathematics topics.
Related questions
Walk the z-scale left to rightSwipe each z-score to its sideKnock out the z-score mythsDrop each trait into the right curveLine up three tiles that agreeA coin is flipped 100 times. The number of heads has a mean of 20 and a standard deviationA doctor reports that a patient's blood pressure has a z-score of 1.75. Which reading is cA test score sits at the 90th percentile. What does that position mean?