Analysis of Variance (one way ANOVA)

Case

A researcher was interested in the effects of hints on anagram solution. The time it took a participant o solve five eight-letter anagrams was measured. The same five anagrams were used in three conditions:

· First Letter (where the first letter if the word was given)

· Last Letter (where the last letter was given)

· No letter (where no help was given)

Thirsty participants were chosen and ten were randomly allocated to each condition. The number of minutes it took to solve the five anagrams was recorded.

Is there an effect of type of hint on solution times?

Solution

Using R

time <- c(15,20,14,13,18,16,13,12,18,11,21,25,29,18,26,22,26,24,28,21,28,30,32,28,26,30,25,36,20,25)
condition <- c(rep("X1",10), rep("X2",10), rep("X3",10))
anagram <- data.frame(time, condition)
results <- aov(time ~ condition, data = anagram)
summary(results)

##             Df Sum Sq Mean Sq F value   Pr(>F)    
## condition    2  886.7   443.3   33.25 5.22e-08 ***
## Residuals   27  360.0    13.3                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1