Question: A developmental psychologist would like to determine how much fine motor skill improves for children from age 3 to age 4. A random sample of n=15 3 year olds and a second sample of n=15 4 year olds are obtained. Each child is given a manual dexterity test that measures fine motor skills. 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 answers from b and c, do these data indicate a significant change using a two tailed test with a= .05? Is the difference significant with a= .01?