Download Ch 10.3

𝐶ℎ. 10.3 𝑀𝑒𝑎𝑠𝑢𝑟𝑒𝑠 𝑜𝑓 𝑉𝑎𝑟𝑖𝑎𝑡𝑖𝑜𝑛
Range is the difference between the largest and smallest number in a
sample.
Deviations from the mean are the differences found by subtracting the
mean from each number is a distribution.
Square of Deviation is square the deviations from the mean so we do not
get negative value of the data.
Population Variance is the sum of square of deviation will divide by the
number of items in the original list.
Sample Variance
Sample standard Deviation is the square root of the sample variance.
Standard Deviation for a Grouped distribution is
Ex1. Find the range for each given data set for a small sample of people.
a) Price paid for last haircut(with tip)
10, 0, 15, 30, 20, 18, 50, 120, 75, 95, 0, 5
b) Amount spent for last vehicle servicing:
30, 19, 125, 150, 430, 50, 225
Ex2. Find sample variance for the following sample of ages.
32, 41, 47, 53, 57
Ex3. Find the standard deviation for the following sample of the lengths
(in minutes) of eight consecutive cell phone conversations by one person:
2, 8, 3, 2, 6, 11, 31, 9
Ex4. Find the standard deviation for a sample of the number of miles
traveled by various people to a vacation location:
135, 60, 50, 425, 380