Confidence Intervals w/two samples

#1
in a classic study of problem solving, katona demonstrated that people whoa re required to figure out a problem on their own will learn more than people who are given the solution. One group of participants is presented with a series of problems that hey must figure out. second group sees the sam eproblems but gets an explanation of the solutions. Later both groups are given a new set of similar problems and their problem-solving scores are as follows:

On their own
n=10
M=78
SS=1420

Given Solutions
n=15
M=66
SS=2030

ss stands for sum of squares NOT standard deviation



MAKE A 95% CONFIDENCE INTERVAL ESTIMATE OF THE MEAN DIFFERENCE.