用Pyhton完成方差分析的代码实现,要求代码可以读取一段带有分组标签的数据,检验分组数据是否对齐,逐步计算总体均值、组内平方和、组间平方和、总平方和、组间均方差、F值,并作F检验
时间: 2023-06-17 19:02:51 浏览: 78
以下是用Python实现方差分析的代码示例:
```python
import pandas as pd
from scipy import stats
# 读取数据文件并检查分组标签是否存在
data = pd.read_csv('data.csv')
if 'group' not in data.columns:
raise ValueError('Group label not found in data')
# 检查分组数据是否对齐
group_sizes = data.groupby('group').size()
if len(group_sizes.unique()) > 1:
raise ValueError('Group sizes are not equal')
# 计算总体均值
grand_mean = data['value'].mean()
# 计算组内平方和
group_sums = data.groupby('group')['value'].sum()
group_means = data.groupby('group')['value'].mean()
group_sizes = data.groupby('group').size()
ss_within = ((data['value'] - group_means[data['group']]) ** 2).sum()
# 计算组间平方和
ss_between = ((group_means - grand_mean) ** 2 * group_sizes).sum()
# 计算总平方和
ss_total = ((data['value'] - grand_mean) ** 2).sum()
# 计算组间均方差和F值
df_within = data.shape[0] - len(group_sizes)
df_between = len(group_sizes) - 1
ms_within = ss_within / df_within
ms_between = ss_between / df_between
f_value = ms_between / ms_within
# 进行F检验
p_value = stats.f.sf(f_value, df_between, df_within)
# 输出结果
print('Grand mean:', grand_mean)
print('SS_within:', ss_within)
print('SS_between:', ss_between)
print('SS_total:', ss_total)
print('MS_within:', ms_within)
print('MS_between:', ms_between)
print('F-value:', f_value)
print('P-value:', p_value)
```
在此示例中,我们假设数据文件名为`data.csv`,其中包含两列:`group`和`value`。首先,我们检查数据中是否存在`group`列,如果不存在,则引发`ValueError`异常。然后,我们检查分组数据是否对齐,如果组大小不相等,则引发`ValueError`异常。接下来,我们计算总体均值、组内平方和、组间平方和、总平方和、组间均方差和F值,并使用`scipy.stats.f.sf`函数进行F检验。最后,我们输出计算出的结果。
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