# Developed by
# Register Number: DurgaDevi P
# Name: 212220230015

import numpy as np
import math
import scipy.stats
X=[0,1,2,3,4,5,6]
f=[153,169,72,31,12,6,2]
n=6
N=np.sum(f)
mean=np.inner(X,f)/N
Prob=list(); E=list(); xi=list()
print("  X P(X=x) Obs.Fr  Ex.Fre   xi ")
print("----------------------------------")
for x in range(7):
    Prob.append(math.exp(-mean)*mean**x/math.factorial(x))
    E.append(Prob[x]*N)
    xi.append((f[x]-E[x])**2/E[x])
    print("%2.2f %2.2f  %4.2f   %3.2f   %3.2f"%(x,Prob[x],f[x],E[x],xi[x]))
print("----------------------------------")
cal_chi2=np.sum(xi)
print("Calculated value of Chi square is %4.2f"%cal_chi2)
tab_chi2=scipy.stats.chi2.ppf(1-.01, df=n)
print("Table value of Chi square at 1  level is %4.2f"%tab_chi2)
if cal_chi2<tab_chi2:
    print("The given data can be fitted in Poissson distribution at 1% LOS")
else:
    print("The given data cannot be fitted in Poisson distribution at 1% LOS")