Practice Problem ANSWERS: Correlation

Item 1

What is the correlation between these two variables:

Stress         Sense of Humor 
    4                     2 
  10                     8 
  12                   11 
    5                     3 
    7                     8 
    6                     7 
    2                     3 
  14                   13

SSx =    120.00
SSy =    110.88
SSxy =  108.50
r =   .94

Item 2

What is the correlation between these two variables:

Laughter     Statistics 
    11                 19 
      3                   6 
      5                   6 
    15                 12 
      7                   8 
      6                   7 
      9                 14

SSx =     98.00
SSy =   145.43
SSxy =   85.00
r =   .71

Item 3

How much variance is accounted for between these two variables:

Strength        Speed 
    12                 3 
      9                 7 
      6                 9 
      3               11 
      1               15 
      7                 6

SSx =      79.33
SSy =      87.50
SSxy =  - 80.00
r =    - .96
r² =   .92 or 92% of the mutual variance is accounted for

Item 4

What is the correlation between these two variables:

Strength         Peace
    2                     2 
    6                     5 
    7                     8 
  14                   19 
  15                   12 
    9                     8 
    4                     5

SSx =     142.86
SSy =     189.71
SSxy =   147.57
r =   .896
Just for practice here is the r² =   .80 or 80% of the mutual variance

NOW YOU CHOOSE:
    Day 5: Correlation
    Bit More About Correlation
    Even More About Correlation
    Calculate Correlation
    Practice Problems
    More Practice Problems
    Word Problems
        Sim1            Sim2             Sim3
        Sim4            Sim5             Sim6
        Sim7            Sim8             Sim9
    Basic Facts About Correlation
    Vocabulary
    Formulas
    Quiz 5
    Summary