Introduction to Stata 8 - (GRIPS

11.2. Continuous variables
oneway [R] oneway
compares means between two or more groups (analysis of variance):
oneway price type [ , tabulate noanova]
. oneway price type , tabulate
type of | Summary of price per 75 cl bottle
wine | Mean Std. Dev. Freq.
------------+------------------------------------
1. red | 48.15 12.650239 15
2. white | 42.590909 20.016952 11
3. rosé | 43.45 17.375268 6
4. undeterm | 59.616666 15.821924 3
------------+------------------------------------
Total | 46.58 16.304104 35
Analysis of Variance
Source SS df MS F Prob > F
------------------------------------------------------------------------
Between groups 780.660217 3 260.220072 0.98 0.4162
Within groups 8257.34954 31 266.366114
------------------------------------------------------------------------
Total 9038.00975 34 265.823816
Bartlett's test for equal variances: chi2(3) = 2.3311 Prob>chi2 = 0.507
The table, but not the test, could also be obtained by;
tabulate type , summarize(price) [R] tabsum
anova [R] anova
Similar to oneway, but handles a lot of complex situations.
table [R] table
table is a flexible tool for displaying several types of tables, but includes no statistical tests.
To obtain the same table as in the oneway example:
table type , content(n price mean price sd price)
Here comes the mean price distribution by two variables. The format option gives a
nicer display.
. table type rating , content(mean price) format(%9.2f)
----------------+------------------------------------------------------
| quality rating
type of wine | 1. poor 2. acceptable 3. good 4. excellent
----------------+------------------------------------------------------
1. red | 51.20 41.45 52.09 34.95
2. white | 76.95 44.20 32.95 37.95
3. rosé | 72.95 45.95 40.95
4. undetermined | 55.95 45.95 76.95
----------------+------------------------------------------------------
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