If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Statistics and probability

Course: Statistics and probability > Unit 3

Lesson 5: Variance and standard deviation of a sample
Math
Statistics and probability
Summarizing quantitative data
Variance and standard deviation of a sample
© 2023 Khan AcademyTerms of usePrivacy PolicyCookie Notice

Sample and population standard deviation

Google Classroom
You might need: Calculator

Problem

You have found the following ages (in years) of all 4 bears at your local zoo:
5, comma, 4, comma, 6, comma, 39
What is the average age of the bears at your zoo? What is the standard deviation? Round your answers to the nearest tenth.
Average age:
\quad
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
years old
Standard deviation:
\quad
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
years
Stuck?
Stuck?