A research study of 30 households in Baniyas showed that the mean pH level in drinking water was 6.92 with a standard deviation of 0.36. Construct a 90% confidence interval

for the mean pH level in household drinking water in Baniyas. O (6.791, 7.049) (6.812, 7.028) (6.751, 7.089) (6.808, 7.032)