Measures of Dispersion
This lecture series discusses measures of dispersion (interquartile range, variance, and standard deviation). Watch these videos and complete the interactive exercises.
Practice
Sample standard deviation - Answers
1. The standard deviation of the amounts is 
gigabytes.
2. The standard deviation is
![s_{x}=\sqrt{\dfrac{(21-47)^{2}+(28-47)^{2}+\cdots+(70-47)^{2}}{7}}\](https://learn.saylor.org/filter/tex/pix.php/92e6b35873803b25e9b576b614b25c96.svg "s_{x}=\sqrt{\dfrac{(21-47)^{2}+(28-47)^{2}+\cdots+(70-47)^{2}}{7}}\")
3. Jerry's error is that his denominator is incorrect.
4. The standard deviation of the times is 
minutes.