1. A psychologist was interested in the effect of Vitamin A deficiency on maze learning rats. A group of nine rats learned a simple maze. Next, these same rats were deprived of Vitamin A for six weeks and were then tested again on their ability to learn a second maze equal in difficulty to the first. The scores represent the number of maze errors made under the two treatment conditions. Perform an appropriate two-tailed test of the significance of the mean difference.