def pooled_standard_deviation(input_variances):
 return sqrt(mean(square([float(i) for i in input_variances])))

def pooled_standard_deviation ( input_variances ) : return sqrt ( mean ( square ( [ float ( i ) for i in input_variances ] ) ) )
returns the average standard deviation for a list of st devs input is a list of floats output is a single float value .