Scala and Spark for Big Data Analytics

Standard deviation

Standard deviation is the square root of the variance (see previously).

The stddev API has several implementations, as follows. The exact API used depends on the specific use case:

def stddev(columnName: String): ColumnAggregate function: alias for stddev_samp.def stddev(e: Column): ColumnAggregate function: alias for stddev_samp.def stddev_pop(columnName: String): ColumnAggregate function: returns the population standard deviation of the expression in a group.def stddev_pop(e: Column): ColumnAggregate function: returns the population standard deviation of the expression in a group.def stddev_samp(columnName: String): ColumnAggregate function: returns the sample standard deviation of the expression in a group.def stddev_samp(e: ...