posted by Heather .
An apple grower is trying to produce larger fruit by using a new fertilizer. The usual fertilizer produces fruit with a mean diameter of 8.7 cm. Two new fertilizer brands are under consideration, with the following experimental results:
BRAND A: n = 10, mean = 9.5 cm, s = 4 cm BRAND B: n = 10, mean = 10.8 cm, s = 3 cm
Calculate the 98% confidence interval for the true difference between the means of the two brands. 
Do you think that Brand B is significantly better than Brand A?