For 2 years I carried on a running argument with my daughter concerning hand calculators.

She wanted one. I maintained that children who use calculators never learn to do arithmetic correctly, whereas she maintained that they do. To settle the argument, we selected five of her classmates who had calculators and five who did not, and made a totally unwarranted assumption that the presence or absence of calculators was all that distinguished these children. We then gave each child three 10-point tests (addition, subtraction, and multiplication), which they were required to do in a very short time in their heads. The scores are as follows:

Addition Subtraction Multiplication Calculator owners 85 3 7 5 2 9 7 3 6 3 1 85 1 Addition Subtraction Multiplication Non-calculator owners 10 7 6 76 5 65 5 97 8 96 9

a. Run the analysis of variance.

b. Do the data suggest that I should have given in and bought my daughter a calculator? (I did anyway. She is now in her late 30s and is a fully certified actuary—so what do I know?)