148k views
5 votes
How can I find how many standard deviations away from the mean a value is by using the empirical rule?

2 Answers

0 votes

Answer:

The first part of the empirical rule states that 68% of the data values will fall within 1 standard deviation of the mean. To calculate "within 1 standard deviation," you need to subtract 1 standard deviation from the mean, then add 1 standard deviation to the mean. That will give you the range for 68% of the data values.

197 − 46 = 151 197 + 46 = 243

The range of numbers is 151 to 243

The second part of the empirical rule states that 95% of the data values will fall within 2 standard deviations of the mean. To calculate "within 2 standard deviations," you need to subtract 2 standard deviations from the mean, then add 2 standard deviations to the mean. That will give you the range for 95% of the data values.

197 − 2 ⋅ 46 = 105 197 + 2 ⋅ 46 = 289

The range of numbers is 105 to 289

Finally, the last part of the empirical rule states that 99.7% of the data values will fall within 3 standard deviations of the mean. To calculate "within 3 standard deviations," you need to subtract 3 standard deviations from the mean, then add 3 standard deviations to the mean. That will give you the range for 99.7% of the data values.

197 − 3⋅ 46 = 59 197 + 3 ⋅ 46 = 335

The range of numbers is 59 to 335

Finally, we can use the symmetry of the bell curve to further divide up the percentages.

2.35% of the data values will lie between 59 and 105

13.5% of the data values will lie between 105 and 151

34% of the data values will lie between 151 and 197

34% of the data values will lie between 197 and 243

13.5% of the data values will lie between 243 and 289

2.35% of the data values will lie between 289 and 335

User Jpishko
by
8.4k points
1 vote
The Empirical Rule states that 99.7% of data observed following a normal distribution lies within 3 standard deviations of the mean. Under this rule, 68% of the data falls within one standard deviation, 95% percent within two standard deviations, and 99.7% within three standard deviations from the mean.
User RandomWhiteTrash
by
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories