Practice Problem ANSWERS: Dispersion

Item 1

Calculate the range of the following scores:

19
15
  8
  5
  5
  2

High Score 19
Low Score    2
Range        17

Item 2

Calculate the range and SS of the following scores:

11
  9
  8
  7
  5
  7

High Score      11
Low Score         5
SumX              47
SumX²          389
(SumX)²      2209
N                      6
SS              20.83
variance    3.47 (if a population) or 4.17 (if a sample)

Item 3

Calculate the variance of the following population:

18
  9
  7
  5
  4
  2

SumX              45
SumX²          499
(SumX)²      2025
N                      6
SS                 161.50
variance         26.92

Item 4

Calculate the SS, variance and stdev of the following population:

  3
18
  9
  6
10
  6
  4

SumX                56
SumX²            602
(SumX)²            3136
N                       7
SS                  154
variance           22
stdev                 4.69

Item 5

Calculate the range, SS, variance and stdev of the following sample:

  12
    3
    9
    5
    5
    5
    7
  11
 14
– 1

Range     15
N            10
SS          186
variance  20.67 (it is a sample, so it is Sum of Squares divided by N-1)
The standard deviation would be 4.55

NOW YOU CHOOSE:
    Day 3: Dispersion
    A Bit More About Dispersion
    Even More About Dispersion
        Range
        MAD
        Sum of Squares
        Variance
        Standard Deviation
    How To Calculate
        Range
        MAD
        Sum of Squares
        Variance
        Standard Deviation
    Formulas For Dispersion
    Practice Problems
    More Practice Problems
    Basic Facts About Dispersion
    Vocabulary
    Quiz 3
    Summary