Suppose a farmer tries two different treatments on crops Tre

Suppose a farmer tries two different treatments on crops. Treatment A is carried out on 10 different acre-sized plots, and yields an average yield of 180 bushels. The sample standard deviation among the plots treated with Treatment A is 20 bushels. Treatment B is given to 12 different plots, and yields an average of 195 bushels. The sample standard deviation for treatment B is 25 bushels. The standard error of the difference in sample averages equals (round to two decimals)

Solution

              
Calculating the standard deviations of each group,              
              
s1 =    20          
s2 =    25          
              
Thus, the standard error of their difference is, by using sD = sqrt(s1^2/n1 + s2^2/n2):              
              
n1 = sample size of group 1 =    10          
n2 = sample size of group 2 =    12          

Thus,

sD =    9.596006114 = 9.60 [ANSWER, STANDARD ERROR OF THE DIFFERENCE]