An educator wants to determine whether early exposure to school will affect IQ. He enlists the aid of the parents of 12 pairs of preschool-age identical twins who agree to let their twins participate in this experiment. One member of each twin pair is enrolled in preschool for 2 years while the other member of each pair remains at home. At the end of the 2 years, the IQs of all the children are measured. The results follow.

IQ

Twin at

Pair preschool Twin at home

1 110 114

2 121 118

3 107 103

4 117 112

5 115 117

6 112 106

7 130 125

8 116 113

9 111 109

10 120 122

11 117 116

12 106 104

Does early exposure to school affect IQ? Use = 0.05 (2 tail).