Formula: ANOR

SSregression = SStotal * rsquared

SSerror = SStotal * (1- rsquared)

SStotal = SSy

df(regression) = k – 1

df(error) = N – k

df(total) = N-1

F = mean squares regression divided by means squares error

 

NOW YOU CHOOSE:
    Day 7: Probability
    Bit More About Probability
    Even More About Probability
    Even More About ANOR
    Calculate ANOR
    Practice Problems
    More Practice Problems
    Word Problems
        Sim1       Sim2        Sim3
    Basic Facts About Probability
    Vocabulary
    Formulas
    Quiz 7
    Summary

Formula for Central Tendency

MEAN.

You probably already know this formula. A mean is the average of scores. We like to use it becuase we don’t have to arrange the scores in any particular order before calculating it. We just add up all the numbers and divide by the number of scores. In statistical vocab we “sum” the numbers and divided the sum by N (the number of scores).

∑X/N

MEDIAN

A median requires that we put the numbers in order (from high to low, or low to high). The median is the score in the middle (if there are an odd number of scores) or the average of the two middle-most scores (if there are an even number of scores). That too much work, so we prefer the mean.

There is no easy formula for median.

MODE

The mode is the most popular score (most common). If you plot a distribution, the mode will be the highest spot on the distribution. It will be the top of the mountain. If your mountain has more than one peak, the distribution will be bimodal (2 high spots) or multimodal (several high spots).

There is no easy formula for mode.

NOW YOU CHOOSE:
   Day 2: Central Tendency
   A Bit More About Central Tendency
   Even More About Central Tendency
   More Examples
      More Mean Examples
      More Median Examples
      Median Is Middle Of Distribution
      More Mode Examples
   Impact of Outlying Scores
      On The Mean
      On The Median
      On The Mode
   How To Calculate Central Tendency
      Calculating The Mean
      Calculating The Median
      When There’s No Middle-Most Score
      Calculating The Mode
   Formulas For Central Tendency
   Basic Facts About Central Tendency
   Vocabulary
   Quiz 2
   Summary

 

Formula For Correlation

 

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 

Formula For Regression

 

Formula for slope:      

Formula for the Y intercept:

Formula for a straight line:

Standard Error of Estimate:

 

Formula For Student’s t

Conceptually, the t-test is like a z score:

 

 

To calculate it, use this formula:

 

 

NOW YOU CHOOSE:
    Day 8: Student’s t-Test
    Bit More About t-Test
    Even More About t-Test
    How to Calculate t-Test
    Practice Problems
    More Practice Problems
    Word Problems
        Sim1           Sim2            Sim3
        Sim4           Sim5            Sim6
        Sim7           Sim8            Sim9
    Basic Facts About t-Test
    Vocabulary
    Formulas
    Quiz 8
    Summary

Formula For F

 

 SSx = SS1 + SS2 + SS3 …

F = mean squares between divided by means squares within

 

NOW YOU CHOOSE
    Day9: 1-Way ANOVA
    Bit More About 1-Way ANOVA
    Even More About 1-Way ANOVA
    Calculate 1-Way ANOVA
    Practice Problems
    More Practice Problems
    Word Problems
        Sim1        Sim2         Sim3
        Sim4        Sim5         Sim6
        Sim7        Sim8         Sim9
    Vocabulary
    Formulas
    Quiz 9
    Summary

Formula For z-Score

 

 

 

 

Formulas For Dispersion

 

 

 

Variance (population) = SS/N

Variance (sample) = SS/(N-1)

Standard Deviation = square root of variance

 

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