independent and dependent variables?

Question

if i am conducting an experiment to determine the effect of temperature on the growth rates of dandelions and my experiment includes several boxes of young dandelions exposed to a variety of temperature, what are my dependent and independent variables?( is my independant variable the temp and my dependent variable the dandelions)?

also when I illustrate my results should i make a line graph or a histogram?

Answer 1

The "dependent" variable is so-called because it depends on other factors (i.e. independent variables) which perhaps you control. In this case, you're determining how growth is determined by temperature, so your metric for growth (e.g. plant weight) is your dependent variable and temperature is your independent variable.

Plant weight (biomass) is a better measure than plant height since it more accurately indicates growth. Choose a good metric is very important; a bad choice can lead to confusing or misleading results.

Normally your independent variable goes on the X axis and your dependent variable on the Y axis (for a 2-dimensional graph, which is not always adequate). Whether you choose a histogram or graph depends on if the variable is continuous or discrete. In this case it doesn't really matter which you choose.

More important than the type of graph is the statistical method you choose to test your hypothesis. Perhaps a student's t-test would do in your case. It's relatively easy to understand so it's a good way to get exposed to hypothesis tests.

Perhaps the most important thing to worry about is another kind of variable, the "confounding variable". This is an independent variable you haven't measured which affects the dependent variable but you fail to take it into consideration. For example, if you had three test groups at different temperatures, but they received different amounts of light and you did not correct for this, then the effect of light would confound/confuse your analysis. It's difficult to correct for differences in light, so make sure all get the same amount of light. Eliminating confounding variables is not always easy (moreso in social science than hard sciences).

Good luck!

P.S. I'll leave you with a thinking question too -- why did I say biomass is better than plant height?

Answer 2

yes, the dependent variable is the factor that changes, depending on the value of the independent variable. The dandelion growth is affected by the temperature. But the temperature is not affected by the dandelion growth. The independent affects the dependent but not the other way round!

Answer 3

The terms "dependent variable" and "independent variable" are used in similar but subtly different ways in mathematics and statistics as part of the standard terminology in those subjects. They are used to distinguish between two types of quantities being considered, separating them into those available at the start of a process and those being created by it, where the latter (dependent variables) are dependent on the former (independent variables). In traditional calculus, a function is defined as a relation between two terms called variables because their values vary. Call the terms, for example, x and y. If every value of x is associated with exactly one value of y, then y is said to be a function of x. It is customary to use x for what is called the "independent variable," and y for what is called the "dependent variable" because its value depends on the value of x.[1] Therefore, y = x2 means that y, the dependent variable, is the square of x, the independent variable.[1][2] The most common way to denote a "function" is to replace y, the dependent variable, by f(x), where f is the first letter of the word "function." Thus, y = f(x) = x2 means that y, a dependent variable, a function of x, is the square of x. Also, in this form, the expression is called an "explicit" function of x, contrasted with x2 − y = 0, which is called an "implicit" function.[

Answer 4

The independent variable temperature will possibly have an effect upon the dependent variable growth rate.
y= a +bx

Answer 5

Hi:
The independent variable is the one you have control of.
The dependent variable is the one which "depends" upon the independent one.
You cannot "grow" the plant, but you can control variables which affect its growth ... of which temperature is one.
Temperature is the independent variable (i.e. the one you control) and dandelion growth is the dependent variable.
Put your independent variable on the X-Axis and the dependent on the Y.

Answer 6

independant variable is going to be what you change. which in this case looks like the temperature.

Dependant variables are everything that changes in response to your independant variable. they are "dependant" on it. In this case, height, growth rate (inches per day), and maybe health.

Make sure you don't change anything else but the temperature. (this may be hard to control, you might want to go with something easier like giving each group different kinds of water or something)

Answer 7

you got your independent variable right, but the dependent variable would be the growth of the dandelions