Contents
How to compensate for missing values in a dataset?
This works by calculating the mean/median of the non-missing values in a column and then replacing the missing values within each column separately and independently from the others. It can only be used with numeric data. Easy and fast. Works well with small numerical datasets. Doesn’t factor the correlations between features.
What happens when you remove outliers from a data set?
By removing outliers, you’ve explicitly decided that those values should not affect the results, which includes the process of estimating missing values. Both cases suggest removing outliers first, but it’s more critical if you’re estimating the values of missing data.
How does k-NN compensate for missing data?
K-NN is quite sensitive to outliers in the data ( unlike SVM) This type of imputation works by filling the missing data multiple times. Multiple Imputations (MIs) are much better than a single imputation as it measures the uncertainty of the missing values in a better way.
Which is more accurate for Missing Data SVM or KNN?
Can be much more accurate than the mean, median or most frequent imputation methods (It depends on the dataset). Computationally expensive. KNN works by storing the whole training dataset in memory. K-NN is quite sensitive to outliers in the data ( unlike SVM) This type of imputation works by filling the missing data multiple times.
How does imputation try to predict missing values?
It is quite similar to regression imputation which tries to predict the missing values by regressing it from other related variables in the same dataset plus some random residual value. It tries to estimate values from other observations within the range of a discrete set of known data points.
How to impute missing entries in incomplete data sets?
Imputation: Impute the missing entries of the incomplete data sets m times ( m =3 in the figure). Note that imputed values are drawn from a distribution. Simulating random draws doesn’t include uncertainty in model parameters. Better approach is to use Markov Chain Monte Carlo (MCMC) simulation.
Which is better for missing data, imputation or deletion?
Note that imputation does not necessarily give better results. Listwise deletion (complete-case analysis) removes all data for an observation that has one or more missing values. Particularly if the missing data is limited to a small number of observations, you may just opt to eliminate those cases from the analysis.