Assume that on 12 test areas different wheat types were planted. After the harvest, these areas resulted into following yield per hectare 35.5; 33.7; 37.8; 31.2; 37.2; 34.1; 35.8; 36.6; 37.1; 34.9; 36.6 and 34.0. From experience we know that the yields per hectare are independent and normally distributed random variables with the parameters $\mu$ and $\sigma^2 = 3.24$. What is the 95\% confidence interval for the estimated mean yield per hectare? [34.17, 36.58] Something else [34.52, 36.23] [34.36, 36.39]