Say that in last year's Leaving Cert English exam, the average mark achieved was 62.1%. A year later, the Dept of Education wants quick feedback on whether the standard has changed. A random sample of 100 scripts are assessed and marked. Their average mark is 65.2% with a standard deviation of 12.4%
Conduct a test of the hypothesis that the standard has changed, using a 95% level of confidence. Report and interpret your findings.
This file contains information on
gender and work hours for a UK sample (
use http://teaching.sociology.ul.ie/so5041/labs/week11a). Use summaries and graphs to
get a sense of the male-female differences, and then use an
independent sample t-test (i.e.,
by(groupvar); replacing the variable names in italics
with the names of the appropriate variables).
This data file (
use http://teaching.sociology.ul.ie/so5041/labs/correl) contains six pairs of
Y2 etc. First, graph all six pairs in scatterplots.
Y2. What sort of
association do you see in each case (positive, negative, none,
strong, weak)? Make a guess what the value of the correlation
coefficient might be (write it down).
For each graph, get the correlation coefficient: e.g.,
corr x1 y1. How do the reported correlation
coefficients correspond with those you guessed?
With the data set ocorr.dta (
use http://teaching.sociology.ul.ie/so5041/ocorr), explore the
correlations between the variables it contains, graphically and with the