Experimental Design B/C

[XJcwolfyX]

In # 13 (conclusion), how do you guys write this one when you do the ending of your experiment: "Reasons to accept/reject hypothesis given".
I am having trouble with this one.

[butter side up]

In # 13 (conclusion), how do you guys write this one when you do the ending of your experiment: "Reasons to accept/reject hypothesis given".
I am having trouble with this one.

This is basically how you conclude your experiment. We usually follow this format:
Our hypothesis was [hypothesis (not including rationale)]. We accept/ reject our hypothesis because [reasons, usually along the lines of 'our data shows a clear trend of x having this effect on y']

For example, if you were doing an experiment involving the height of a ramp affecting the distance a car travels, it might look like this:
Our hypothesis was that an increased ramp height would result in an increased distance a car travels. We accept our hypothesis because our data supports it by demonstrating a clear trend of increased ramp height resulting in an increased distance traveled.

A rejected hypothesis based on negative data might look like:
Our hypothesis was that increased mass of a ball would result in a higher rebound bounce. We reject our hypothesis because our data does not support it. The data actually shows a negative correlation, suggesting that greater mass decreases the height to which a dropped ball would bounce.

A rejected hypothesis based on scattered data might look like:
Our hypothesis was that an increased boil time would result in a longer time an egg would be able to spin. We reject our hypothesis because our data does not support our hypothesis. There is no trend or relationship that is noticable from our experiment, and we found no correlation between length of time boiled and spin time.
I hope this helps!

[whiteboard]

Does anyone have any suggestions as to some possible options for "other appropriate statistic used"?

[quizbowl]

Athens wasn't bad - gave us a bunch of metal nuts, string, two blocks of wood and duct tape. They defined Newton's Three Laws for us and asked us to design an experiment around one of them. When in doubt, pendulum. It looked like at least half of the competitors used one.

[EpicFailure]

Does anyone have any suggestions as to some possible options for "other appropriate statistic used"?

On sample write-ups, I've seen people use x bar instead of simply writing average to make it Division appropriate. There is also LSRL values & line (w/ residual) and standard deviation.

[FawnOnyx]

What exactly are you supposed to give for a "measure of central tendency" for Division C Statistics? Is it still just mean, median or mode, even though that's a separate item? Or is it something else? Our team got marked off at an invitational for not having it, even though I think we listed mean, median, and mode. Maybe we just had to label the mean the "central tendency"

[butter side up]

What exactly are you supposed to give for a "measure of central tendency" for Division C Statistics? Is it still just mean, median or mode, even though that's a separate item? Or is it something else? Our team got marked off at an invitational for not having it, even though I think we listed mean, median, and mode. Maybe we just had to label the mean the "central tendency"

That would be a good start- we've often found that it is really easy to miss something that is written down, especially considering the scorer has to read through many of these really fast. We also include standard deviation and averages (mean) for x and y overall, and for x and y at each level of x we test.

Does anyone know if you are allowed to have the rubric with you during the event? I don't think the rules address this, and it seems like it would be helpful to be able to refer to the rubric to make sure you don't forget anything.

The most common form I've seen does not give you a rubric, but the pages you are given do have the major headings listed on them by number. IE: You are given a certain space for your problem statement, which is labeled problem statement, but does not have the individual point breakdown for not being a yes/ no question, etc.

[kayken13]

For standard deviation, are we supposed to use find the population standard deviation or sample standard deviation?

Also, are we supposed to find standard deviation for each trial set up, for the final numbers, or both?

[BoldlyGoingNowhere]

What does it mean that variables must be "operationally defined"?

[piisamazing]

For standard deviation, are we supposed to use find the population standard deviation or sample standard deviation?

Also, are we supposed to find standard deviation for each trial set up, for the final numbers, or both?

As far as I know you find standard deviation for the final numbers so you can avoid having to deal with outliers and mistrials. Also, you find population standard deviation.

[BoldlyGoingNowhere]

How do you give example calculations for the quantitative data?

[foreverphysics]

Just, y'know, put down all the math you did to solve.

[EpicFailure]

Just, y'know, put down all the math you did to solve.

You could also write the formulas and put down the math for one set of data. For example, an example calculation for average would look something like:

Average: mean of all numbers = (Trial 1 + Trial 2 + Trial 3)/3 = (21.1+20.5+22.5)/3 = 21.4

[foreverphysics]

How long would you suggest practicing with your partner(s)? Seeing as it's 12 days before Regionals and I haven't yet practiced with either of them, this is a pretty big problem.

[piisamazing]

How long would you suggest practicing with your partner(s)? Seeing as it's 12 days before Regionals and I haven't yet practiced with either of them, this is a pretty big problem.

not really. i didnt practice with my partners, and we made 1st place at reigionals. All you need to really do is make sure you can write a hypothesis correctly. the only practice ever do with my partners is to have sample bags and just come up with ideas of possible experiments