import pandas as pd # pandas package를 이용
sample1 = pd.read_excel("http://kanggc.iptime.org/book/data/stat-1.xlsx")
sample1

sample1.info()

#frequencies of each value in grade
df_sample1 = sample1.groupby('grade', as_index = False).agg(n=('grade', 'count'))
df_sample1

print("Frequency of Grade is : ",f'\n{df_sample1}\n')

import matplotlib.pyplot as plt # matplotlib.pyplot package를 이용
import seaborn as sns # seaborn packagem를 이용

sns.barplot(data=df_sample1, x='grade', y='n').set(title='Bar Chart of Test Scorel')

plt.savefig('C:/BOOK/PyBasics/PyStat/code/bar.png')