# Rnote4.1.R

# (c) 2010 by Mary E. Beckman, Linguistics Department, Ohio 
# State University.  Code for use with the Ling 286 textbook 
# Analyzing the Sounds of Languages.

# Shows how to calculate the mean proportional deviation from 
# the expected counts of different outcomes in experiments with 
# a die roll simulator.

# Assign the vectors of observed counts to appropriately named 
# variables, giving names to the counts, to remind yourself 
# which count is for which of the six outcomes of the die roll.
x3 <- c(Ones=1, Twos=4, Threes=1, Fours=1, Fives=2, Sixes=3)
x5 <- c(Ones=18, Twos=22, Threes=25, Fours=19, Fives=17, Sixes=19)
x6 <- c(Ones=1996, Twos=2028, Threes=1955, Fours=2004,	Fives=1982, Sixes=2035)

# Subtract the expected count to get the vector of absolute 
# differences. 
x3-2
x5-20
x6-2000

# Divide that vector by the expected count to get the proportional
# deviation.
(x3-2)/2
(x5-20)/20
(x6-2000)/2000

# Use the abs() function to convert to the absolute value.
abs((x3-2)/2)
abs((x5-20)/20)
abs((x6-2000)/2000)

# Use the mean() function to see the average percentage deviation
mean(abs((x3-2)/2))
mean(abs((x5-20)/20))
mean(abs((x6-2000)/2000))

# Multiply by 100 if you prefer percentages.
mean(abs((x3-2)/2))*100
mean(abs((x5-20)/20))*100
mean(abs((x6-2000)/2000))*100