在散点图上标记异常值

import matplotlib.pyplot as plt
import numpy as np

# 生成示例数据
np.random.seed(0)
x = np.random.normal(0, 1, 100)
y = np.random.normal(0, 1, 100)

# 计算IQR并确定异常值
Q1 = np.percentile(y, 25)
Q3 = np.percentile(y, 75)
IQR = Q3 - Q1
lower_bound = Q1 - 1.5 * IQR
upper_bound = Q3 + 1.5 * IQR

# 标记异常值
outliers = (y < lower_bound) | (y > upper_bound)

# 绘制散点图
plt.scatter(x, y, color='blue', label='Normal Data')
plt.scatter(x[outliers], y[outliers], color='red', label='Outliers')

# 添加图例和标签
plt.legend()
plt.xlabel('X-axis')
plt.ylabel('Y-axis')
plt.title('Scatter Plot with Outliers Marked')

# 显示图形
plt.show()