31. A paired-difference experiment dealing with response latencies for noise detection under two conditions used a sample of twelve 9-month-old children and reported a sample incan difference of 70.1 and standard deviation of 49.4 for the differences (I Morgan and J. Saffran. Child Development, Vol 66, 1995, pp. 911-936). In their discussion, the authors reported a statistic of 4.9 having P <01 for a two-sided alternative. Show how they constructed the statistic, and confirm the P-value.