# Customise column distributions¶

All distributions in `edo`

have settings that can be customised. You can see
all of the currently implemented distributions, and their default settings, on
the `edo.distributions`

reference page. For now, let’s consider the
normal distribution:

```
>>> from edo.distributions import Normal
```

The default bounds are -10 and 10 for the mean, and 0 and 10 for the standard deviation:

```
>>> Normal.param_limits
{'mean': [-10, 10], 'std': [0, 10]}
```

Changing these bounds is as simple as redefining the class attributes:

```
>>> Normal.param_limits['mean'] = [-5, 5]
>>> Normal.param_limits['std'] = [0, 1]
>>> Normal.param_limits
{'mean': [-5, 5], 'std': [0, 1]}
```

Now all instances of normally distributed columns will have a mean between -5 and 5, and a standard deviation between 0 and 1.

In addition to this, hard bounds on the parameters can be set:

```
>>> Normal.hard_limits['mean'] = [-100, 100]
```

These hard limits are meant to stop the parameter limits from shrinking too far.