Homework 3, POLS 8505: MEASUREMENT
THEORY
Due 2 February 2015
- In this problem we are going to redo the Morse Code Problem with the correct data and the correct version of
smacof, namely, with the correct version of
smacofSym:
morse_code.r -- R Program to perform a Non-Metric Multidimensional
Scaling of the Morse code data (set up for Lower Half)
Morse Code Data Lower Half
Morse Code Data Upper Half
- Run morse_code_L1.txt and morse_code_U1.txt through smacof (be sure to use
unique output file names) in 1 to 3 dimensions. To do this change:
ndim=2 to
ndim=1 and
ndim=3.
Report the
Stress values for 1 to 3 dimensions for the two halves
of the data.
- Make two-dimensional Plots for the two halves of the data
(put the 26 letters and 10 integers before the corresponding
coordinates). You can modify the
georgia.r program to do this. Turn in the plots and the
R code. Do the plots look the same?
- In this problem we are going to use blackbox transpose from the
basicspace package in
R.
Download the R programs:
basicspace_big_blackbox_transpose_1968_Therms.r --
R program that performs a basicspace transpose scaling on the 12 Candidate Feeling Thermometers From the 1968 National
Election Study. This version removes the 1500 respondent restriction -- Use with caution!
The program
reads this R program (courtesy of James Lo):
big_blackbox_transpose.R --
R code that creates the function
big_blackbox_transpose which is used in the R program above.
Place the two R programs in the same directory as the first calls the second.
- Run basicspace_big_blackbox_transpose_1968_Therms.r and turn in the plots that it
creates. Adjust the name position vector namepos so that none of the 12
Candidate names overstrike.
- Report summary(result) NEATLY FORMATTED and result$fits NEATLY FORMATTED.
- We are now going to try blackbox transpose on the NES 1968 Urban Unrest and Vietnam 7 point scales to test how
unidimensional they are.
Download the R programs:
The programs
read this R program (courtesy of James Lo):
big_blackbox_transpose.R --
R code that creates the function
big_blackbox_transpose which is used in the R program above.
Place the three R programs in the same directory as the first two call the
third.
- Run basicspace_big_blackbox_transpose_Urban_Unrest_1968.r. Report summary(result)
NEATLY FORMATTED and result$fits NEATLY FORMATTED.
- Run basicspace_big_blackbox_transpose_Vietnam_1968.r. Report summary(result)
NEATLY FORMATTED and result$fits NEATLY FORMATTED.
- In your opinion, are these two scales unidimensional? Explain.
- Work Exercise (6) on pages 100-101 of Analyzing Spatial Models of Choice and Judgment with R.