Hi all,

The "meantest" command provides a simple way to conduct a paired t-test comparing the mean values between TWO series.

The help says:

"""

Paired test

In the primary case (only) the --⁠paired option can be given, to test the null hypothesis that the mean difference between the paired values of the two series arguments is zero. Otherwise, pairing is not assumed.

"""

Take the following example which I would expect to fail as only a single series is provided:

<hansl>

open mrw --quiet

summary gdpgrow --simple

meantest gdpgrow --paired

</>

However, the output is:

"""

Summary statistics, using the observations 1 - 121

for the variable 'gdpgrow' (117 valid observations)

Mean 4.09402

Minimum -0.900000

Maximum 9.20000

Standard deviation 1.89146

Missing obs. 4

Paired difference test

Number of observations = 117

Sample mean paired difference = 3.09402

Null hypothesis: The population mean difference is zero.

Estimated standard error = 0.174866

Test statistic: t(116) = 17.6937

p-value (two-tailed) = 9.72895e-35

"""

It looks as in case no 2nd series is provided, the test compares to a constant series - compare with this:

<hansl>

I guess that should be mentioned in the help text or output. Alternatively, an error may be flagged as two series are expected.

Best

Artur