Question: Measuring Intelligence in Children

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 accompanying table.

a. Is there sufficient evidence to support the claims that there is a difference between the two times? Use a 0.01 sufficient level.

b. Construct a 99 % confidence interval for the mean of the differences. Do the confidence interval limits contain 0? Indicating there is not a sufficient difference between the times of the first and second trials.