计算均值和方差

def solve():
    from sklearn.datasets import load_iris
    import numpy as np
    iris = load_iris()
    sepal_length = iris.data[:, 0]
    mean = np.mean(sepal_length)
    var = np.var(sepal_length)
    print(f"花萼长度均值: {mean:.4f}")
    print(f"花萼长度方差: {var:.4f}")