To analyze Sn in a soil sample, a chemist must prepare the standard calibration curve with the standard addition method. The standard stock solution is 0.2M. 1- To prepare the first diluted standard, he diluted 20 times the stock solution and repeat it five times. The results are: 0.0110.010.0090.008 and 0.012M. a- Calculate the mean b- Calculate the standard deviation. Are the results precise? c- Calculate the relative error for the mean. 2- To prepare the second standard, he diluted 10mL from the stock solution in 50mL. The results are: 0.0390.040.0410.0370.0380.042M a- Calculate the mean b- Calculate the relative error for the mean. Are the results accurate