Funtion to define bounds on the duration of an activity during detection of duration outliers.
duration_within(bound_sd = 3, lower_bound = NA, upper_bound = NA)
| bound_sd | Number of standard deviations from the mean duration which is used to define an outlier in the absence of lower_bound and upper_bound (default value of 3 is used)  | 
    
|---|---|
| lower_bound | Lower bound for activity duration used during outlier detection (expressed in minutes). This means disregarding the sd and bound_sd for lower bound  | 
    
| upper_bound | Upper bound for activity duration used during outlier detection (expressed in minutes). This means disregarding the sd and bound_sd for upper bound  | 
    
No return value, called for side effects