Symmetric Y Error Bars (from asymmetric)
Y values
+--------------------------------------------------------------------------------+
| 4.0                                                                            |
| |                                                                              |
| |                                                                              |
| |                                     -                 - --- Average errors   |
| 3.5                                   -                 -                      |
| |                                                                              |
| |                                     -                 -                      |
| 3.0                                                                      -     |
| |                    -                -                 -                      |
| |                                     -   -             -                -     |
| |                    -         -   -         -   -  -                    -     |
| 2.5                  -      -         -                 -                      |
| |                    -  -             -                 - -              -     |
| |                 -  -                                       -           -     |
| |                                     -                 -       -              |
| 2.0            -     -                -                            -     -     |
| |           -        -                                  -             -  -     |
| |        -                                              -                -     |
| |  -  -                                                                  -     |
| 1.5-                                                    -                -     |
| |  -                                                                           |
| |                                                                        -     |
| 1.0-                                                                           |
| |                                                                        -     |
| |                                                                        -     |
| |                                                                              |
| 0.5                                                                      -     |
| |                                                                        -     |
| +--+-------+--------+--------+--------+--------+--------+--------+-------+---- |
|   1.0     1.5      2.0      2.5      3.0      3.5      4.0      4.5     5.0    |
+--------------------------------------------------------------------------------+
                                    X values