Help with variables question

[HopePressler1]

My son competed in a small science fair and one of the comments the judge made was that he should have used p values.
My son is now going on to a larger fair and he wants to include them. I’m trying to learn about p values so I can help him understand them.
My son asked the questions “Will changing the model rocket engine change the speed, maximum altitude, and parachute deployment of the model rocket?”

He used 4 different types of model rocket engines. Would a p value be calculated for the difference between each engine for speed, maximum altitude and parachute deployment? Would he compare the results between engine 1 to engine 2, 3 and 4? Or would he compare engine 1 to 2 and 2 to 3 and 3 to 4?

We found an online calculator and he was putting in the data and getting the results, but I wasn’t sure how to advise him on which data to compare.

Thank you far your help.
Hope

[norman40]

Hi HopePressler1,

Congratulations to your son for moving on to the larger science fair!

Your son might use t-tests for comparing the rocket engine results. A t-test can be used to estimate the probability (p value) that two mean values are different. A series of t-test calculations could be made to compare all possible pairs of your rocket engines. That is engine 1 compared with engines 2, 3 and 4; engine 2 compared with engines 3 and 4; and engine 3 compared with engine 4. And you'd need to complete the series of t-test calculations for each of the independent variables mentioned in your post.

I hope this helps. Please ask again if you have more questions.

A. Norman