# -*- coding: utf-8 -*-
"""
Created on Thu Jul  8 14:54:29 2021

@author: Sim
"""
import scipy.stats as st
import numpy as np

xx = [89,  91,  98,  78,  80,  85,  88,  87,  90,  92]
df = len(xx)-1

tval, pval = st.ttest_1samp(xx, popmean=90, alternative='less')
print(tval, pval)

tval1 = ( np.mean(xx) - 90 ) / (np.std(xx, ddof=1)/len(xx)**.5)
print(tval1)
pval1 = st.t.cdf(tval1, df)
print(pval1)

cval = -st.t.ppf(.95, df)
if tval < cval:
    print('Reject H0 as ', tval, ' < ',  cval)
else:
    print('Cannot reject H0 as ', tval, ' >= ', cval)

# 신뢰구간(99%)

lbd = np.mean(xx) - st.t.ppf(.995, df) * np.std(xx, ddof=1)/(len(xx)**.5)
ubd = np.mean(xx) + st.t.ppf(.995, df) * np.std(xx, ddof=1)/(len(xx)**.5)
print(lbd, ubd)