How do you treat null/missing values? Name 3 methodologies.
Last Observation Carried Forward (LOCF) & Next Observation Carried Backward (NOCB)
This is a common statistical approach to the analysis of longitudinal repeated measures data where some follow-up observations may be missing. Longitudinal data track the same sample at different points in time. Both these methods can introduce bias in analysis and perform poorly when data has a visible trend
Linear Interpolation
This method works well for a time series with some trend but is not suitable for seasonal data
Seasonal Adjustment + Linear Interpolation
This method works well for data with both trend and seasonality