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 three year old children & a second sample n = 15 four year old are obtained. Each child is given a manual dexterity test that measures fine motor skills. The average score for the children was M = 40.6 with SS = 430 & the average for the younger children was M = 35.4 with SS = 410. Using these data,

[A] Make an interval estimate so you are 99% confident that the real mean difference is in your interval.

[B] Based on your answers from b & c, do these data indicate a significant change using a two-tailed test with alpha=.05? Is the difference significant with alpha=.01?

[C] Make a point estimate of the population mean difference in fine motor skills

[D] Make an interval estimate so you are 95% confident that the real mean difference is in your interval.