One Way Anova

n = ?

n = ?

M1 = ? S1 = ? SS1 = ?

M2 = ? S2 = ? SS2 = ?

3+ Independent Groups One Way ANOVA test Assignment 14 Problems

2 explanations of your data (using directional or non-directional language

depending on the research question)

tx1

tx2

IV tx1

tx2

The independent variable is being manipulated with three or more treatments (hint: with an abstract problem like this, sometimes it helps to put in real treatments, such as IV Pain Relievers with tx1 Ibuprofen and tx2 Tylenol and tx3 Aspirin)

H1: IV had an effect (i.e. there is a difference between the groups due to

the effect of the IV)

H0: IV had no effect (i.e. there is not a difference between the groups due to the effect of the IV; all results are due to chance primarily through

sampling error)

Population µ & σ (unknown)

High Prob. (easy)

Low Prob. (hard)

α = .05 Prob. calcul ation

One Way Anova F test

Step 3: Using Part III of formula sheet, determine the

critical F value 3 groups assumed to be equivalent

Accept H0 (due to chance)

Reject H0 & Accept H1

(due to real effect)

Step 1: Diagram your study (noting the data you are given)

Step 2: Create a table of calculations for each of the terms which you will need to solve the

formulas (not needed in this problem)

low high

Step 4: Calculate the F statistic (see One-Way Anova formula sheet)

1. SSbetween = ? 2. SSwithin = ?

Table of Variances

Step 5: Compare critical F to the calculated F & make a

decision about the H0 hypothesis

Step 6: Report results professionally (see last step of

formula sheet)

x1 x1 2 x2 x2

2 x3 x3 2

(data from each group)

__ __ __ ___ ___ ___ ∑= ∑= ∑= ∑= ∑= ∑=

∑(x1) 2= ∑(x2)

2= ∑(x3) 2=

2 outcomes 2 decisionsn = ?

tx3

tx3 M3 = ? S3 = ? SS3 = ?

F

dfbet = k-1

dfwith = (n1 + n2…+nk) -k

Source SS df S2 F

Between

Within X

Total X X