Question: Mental measurements of young children are often made by giving them blocks and telling them to build a tower as tall as possible. One experiment of block building was repeated a month later, with the times (in seconds) listed in the table below. Is there sufficient evidence to support the claim that there is a difference between the two times? Use a 0.01 significance level.

Child A B C D E F G H I J K L M N O

First

Trial 30 19 19 23 29 178 42 20 12 39 14 81 17 31 52

Second

Trial 30 6 14 8 14 52 14 22 17 8 11 30 14 17 15