Gaussian fit significant figures

Hi - I am having trouble with significant figure in extracting the mean from a Gaussian fit. The fit
prints out:

EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 Constant 1.65433e+02 9.98179e-01 3.95288e-06 -9.89660e-05
2 Mean 6.66537e-01 3.62186e-01 1.40084e-03 3.90489e-05
3 Sigma 4.90069e+01 6.56720e-01 -9.24634e-06 5.63522e-03

Where the mean of the Guassian is given in bold.

But doing
TF1 myfit = (TF1) gr1->GetFunction(“gaus”);
double myMean = myfit->GetParameter(1);

the readout gives:
myMean = 0.7

Where this is not precise enough - I would like 0.6665
How do I alter the number of significant figures?
Thanks.

Hi,

How did you print out the Mean value ? I should look at your full code to understand your problem,

Lorenzo