Question: A development psychologist would like to determine how much fine motor skills improve for children from age 3 to age 4. A random sample of n=15 3-year-old children and a second sample of n=15 4 year-olds are obtained. Each child is given a manual dexterity test that measures fine motor score. The average score for the older children was M=40.6 with SS=430 and the average for the younger children was M=35.4 with SS=410. Using these data,

a) Make a point estimate of the population mean difference in fine motor skills.

b) Make an interval estimate so you are 95% confident that the real mean difference is in your interval.

c) Make an interval estimate so you are 99% confident that the real mean difference is in your interval.

d) Based on your answer from b and c, do these data indicate a significant change using a two-tailed test α=.05? Is the difference significant with α=.01?