text: 
  ybar = 31.2           # sample mean 
  mu0 = 33            # hypothesized value 
  sigma = 8.4       # population standard deviation 
  n = 35                # sample size 
  z = (ybar- mu0)/(sigma/sqrt(n))
  # test statistic
  
  p_value=pnorm(z)
  print(p_value)
  alpha=0.05
  if(p_value>alpha){
    print("we fail to reject H0")
    print(" data do not support the research hypothesis(insufficient evidence).")
  }else{
    print("reject H0")
  }
  