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) and five pairs of children’ completion times are listed below. Test the claim that there is a difference in times between two trials. (a) At a = 5%, use the Classical approach to conclude it. (b) Using the P-value approach to conclude it. Draw the curves.

1^st Trial (A) 33 28 29 26 29

2^nd Trial (B)30 25 24 24 29 .