MINITAB EXAMPLE
One-way ANOVA
252anovaex1 9/10/99
Explanation: The data set has already been prepared and stored as 2f1.mtb. Each
column represents a treatment. The data set is retrieved and the command for
one-way ANOVA is issued. An ANOVA table is produced and a p-value given to the
null hypothesis that the columns are samples from populations with identical
means. The intention here was to do a test with a significance level of 5%.
Since the p-value was 2.7% (below 5%), we reject the null hypothesis. The
program also produces column means and sketches individual confidence intervals
for these means. The overall mean is not supplied.
Minitab Output:
Worksheet size: 100000 cells
MTB > RETR 'C:\MINITAB\2F1.MTW'.
Retrieving worksheet from file: C:\MINITAB\2F1.MTW
Worksheet was saved on 9/10/1999
MTB > print c1-c3
Data Display
Row
C1
C2
C3
1
2
3
4
89
101
87
87
104
120
98
110
86
98
100
96
MTB > aovoneway c1-c3
One-Way Analysis of Variance
Analysis of Variance
Source
DF
SS
Factor
2
632.0
Error
9
516.0
Total
11
1148.0
Level
C1
C2
C3
N
4
4
4
Pooled StDev =
Mean
91.00
108.00
95.00
7.57
MS
316.0
57.3
StDev
6.73
9.38
6.22
F
5.51
p
0.027
Individual 95% CIs For Mean
Based on Pooled StDev
--------+---------+---------+-------(--------*--------)
(--------*--------)
(--------*--------)
--------+---------+---------+-------90
100
110