import statistics

A_rank = [87.24, 91.32, 87.24, 90.30]
print(statistics.stdev(A_rank))

A_rank = [87.31, 32.03, 87.86, 60.85]
print(statistics.stdev(A_rank))

A_rank = [84.12, 80.95, 85.71, 85.71]
print(statistics.stdev(A_rank))

A_rank = [78.57, 77.38, 77.38, 73.80]
print(statistics.stdev(A_rank))

A_rank = [59.32, 67.79, 64.40, 69.49]
print(statistics.stdev(A_rank))