1. model.fitTo(*data, GlobalObservables(mu_obs))
------------------------------------------------

  RooFitResult: minimized FCN value: 68.2482, estimated distance to minimum: 9.80327e-07
                covariance matrix quality: Full, accurate covariance matrix
                Status : MINIMIZE=0 HESSE=0 

    Floating Parameter    FinalValue +/-  Error   
  --------------------  --------------------------
                    mu    5.2717e-02 +/-  8.11e-02
                 sigma    9.7190e-01 +/-  9.73e-02

2. model.fitTo(*data)
---------------------

  RooFitResult: minimized FCN value: 68.2482, estimated distance to minimum: 9.80327e-07
                covariance matrix quality: Full, accurate covariance matrix
                Status : MINIMIZE=0 HESSE=0 

    Floating Parameter    FinalValue +/-  Error   
  --------------------  --------------------------
                    mu    5.2717e-02 +/-  8.11e-02
                 sigma    9.7190e-01 +/-  9.73e-02

3. model.fitTo(*data, GlobalObservables(mu_obs), GlobalObservablesSource("model"))
------------------------------------------------

  RooFitResult: minimized FCN value: 83.7181, estimated distance to minimum: 6.67911e-07
                covariance matrix quality: Full, accurate covariance matrix
                Status : MINIMIZE=0 HESSE=0 

    Floating Parameter    FinalValue +/-  Error   
  --------------------  --------------------------
                    mu    7.4744e-01 +/-  9.68e-02
                 sigma    1.2451e+00 +/-  1.38e-01