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Dependent, Independent, Direct, or Derived Variables

Posted: Sat May 19, 2007 6:14 am
by medlockprice
My Variable Table shows date, time of day data collected,age, height, # of children in family, resting pulse rate, ratio of pulse rate to age, gender,hair color,birth order, & money in wallet. Which are dependent/independent and direct/derived? I'm confused :cry:

Posted: Sat May 19, 2007 7:18 am
by drhamill
Medlockprice,
This is a complex, but important, topic. However, you haven't given me enough info about the question(s) you are asking and to whom to know which variables are what type. Are you intending to use all of the data you've collected? How do you intend to show your results? Graph? Please carefully read the info on the following link and see if that helps:

http://www.sciencebuddies.org/mentoring ... bles.shtml

Posted: Sat May 19, 2007 7:33 am
by medlockprice
drhamill wrote:Medlockprice,
This is a complex, but important, topic. However, you haven't given me enough info about the question(s) you are asking and to whom to know which variables are what type. Are you intending to use all of the data you've collected? How do you intend to show your results? Graph? Please carefully read the info on the following link and see if that helps:

http://www.sciencebuddies.org/mentoring ... bles.shtml

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Does the example of my table below help?

Variable Data Type Dependent/Independent Direct/Indirect
Date: 16May2007 ? ?
Time of day
Data Collected: 1500 ? ?
Age: 43 ? ?
Height: 6'0 ? ?
# of Children
in Family: 5 ? ?
Resting Pulse: 62 ? ?
Ratio of Resting
Pulse to age: 1.5 ? ?
Gender: Male ? ?
Hair Color: Black ? ?
Birth Order: 3 ? ?

Posted: Sat May 19, 2007 7:51 am
by MelissaB
What Drhamill was asking, I think, was: What question(s) are you trying to answer with the data you have gathered? It makes a difference as to which variables are which.

Posted: Sat May 19, 2007 8:31 am
by drhamill
Yes, MelissaB's point is right on.

Here are a few comments and examples to get you started on some possible ways to analyze the data.

In a well controlled study, you would have a single independent variable (the one thing you change), a dependent variable (or variables) = what you measure or observe, and controlled variables (things you keep the same from trial to trial). (However, I recognize it is difficult to control all variables in a survey like you are doing.)

For example, if your question is who has higher blood pressure, people over 25 or people under 25 years of age, your independent variable is age. Your dependent variable (what you observe) is blood pressure. Ideally you would have controlled variables that you keep the same (e.g. gender, body mass index, etc.)

Obviously, you intend to gather a lot of different sorts of data, but I’m not clear how relevant they all are. With the data you have, you could ask for example, who has higher blood pressure, people in families with 0 – 2 kids or more than two kids. In this case, your independent variable is # of kids in the family. You could also ask questions about race and blood pressure or gender and blood pressure, since you have that data too, etc. In each of these cases, it seems the dependent variable (the one you measure / observe) would be blood pressure.

Hope this helps.

Dependent/Independent, Direct/Indirect

Posted: Sun May 20, 2007 4:12 pm
by medlockprice
A science teacher from "Yahoo Answers" answered the data on my chart. They labeled what was Dependent/Independent, Direct/Indirect. Thanks for your input.

Re: Dependent/Independent, Direct/Indirect

Posted: Sun May 20, 2007 4:33 pm
by Louise
medlockprice wrote:A science teacher from "Yahoo Answers" answered the data on my chart. They labeled what was Dependent/Independent, Direct/Indirect. Thanks for your input.


I would read again what others posted here. As the other experts pointed out, you cannot label the variables unless you know what the question is. Unless you gave the person on yahoo more information than you posted here, their response may be incorrect for your experiment.

Good luck with the science fair.

Louise