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What Does Independent Variable Mean In Biology

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Variables in Science: Independent, Dependent and Controlled!

Q: How do you identify the independent and dependent variables?

Ans: An easy way to think of independent and dependent variables is, while conducting the experiment, the independent variable is always the one that we change, and the dependent variable is that which changes because of that. Also, we can think of the independent variable as the cause and the dependent variable as the effect.

How Do You Identify Independent And Dependent Variables In Biology

The independent and dependent variables are the two key variables in a science experiment. The independent variable is the one the experimenter controls. The dependent variable is the variable that changes in response to the independent variable. The two variables may be related by cause and effect.

What Does A Independent Variable Mean In Biology

Here the independent variable is the cause factor. An independent variable is a variable that we can change or control in a scientific experiment. It will represent the cause or reason for an outcome. Therefore, independent variables are the variables which the experimenter changes to test their dependent variable.

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Quiz: Test Your Variable Knowledge

Can you identify the independent and dependent variables for each of the four scenarios below? The answers are at the bottom of the guide for you to check your work.

Scenario 1: You buy your dog multiple brands of food to see which one is her favorite.

Scenario 2: Your friends invite you to a party, and you decide to attend, but you’re worried that staying out too long will affect how well you do on your geometry test tomorrow morning.

Scenario 3: Your dentist appointment will take 30 minutes from start to finish, but that doesn’t include waiting in the lounge before you’re called in. The total amount of time you spend in the dentist’s office is the amount of time you wait before your appointment, plus the 30 minutes of the actual appointment

Scenario 4: You regularly babysit your little cousin who always throws a tantrum when he’s asked to eat his vegetables. Over the course of the week, you ask him to eat vegetables four times.

Independent And Dependent Variables In Research

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Independent and dependent variables are generally used in experimental and quasi-experimental research.

Here are some examples of research questions and corresponding independent and dependent variables.

Research question
  • number of independent variable levels.

Youll often use t tests or ANOVAs to analyze your data and answer your research questions.

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What Is A Control Variable

Experiments also have controlled variables. Controlled variables are quantities that a scientist wants to remain constant, and she or he must observe them as carefully as the dependent variables. For example, in the dog experiment example, you would need to control how hungry the dogs are at the start of the experiment, the type of food you are feeding them, and whether the food was a type that they liked. Why? If you did not, then other explanations could be given for differences you observe in how much they eat. For instance, maybe the little dog eats more because it is hungrier that day, maybe the big dog does not like the dog food offered, or maybe all dogs will eat more wet dog food than dry dog food. So, you should keep all the other variables the same so that you can see only the effect of the one variable that you are trying to test. Similar to our example, most experiments have more than one controlled variable. Some people refer to controlled variables as “constant variables.”

What Are Controlled Variables

A control variable in science is any other parameter affecting your experiment that you try to keep the same across all conditions.

For example, one control variable in the plant growth experiment could be temperature. You would not want to have one plant growing in green light with a temperature of 20°C while another plant grows in red light with a temperature of 27°C.

You want to measure only the effect of light, not temperature. For this reason you would want to keep the temperature the same across all of your plants. In other words, you would want to control the temperature.

Another example is the amount of water you give the plant. If one plant receives twice the amount of water as another plant, there would be no way for you to know that the reason those plants grew the way they did is due only to the light color their received.

The observed effect could also be due in part to the amount of water they got. A control variable in science experiments is what allows you to compare other things that may be contributing to a result because you have kept other important things the same across all of your subjects.

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Understanding Variables In A Science Experiment

  • Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
  • B.A., Physics and Mathematics, Hastings College

Variables are an important part of science projects and experiments. What is a variable? Basically, a variable is any factor that can be controlled, changed, or measured in an experiment. Scientific experiments have several types of variables. The independent and dependent variables are the ones usually plotted on a chart or graph, but there are other types of variables you may encounter.

How Do You Identify A Variable

Independent and Dependent Variables

A variable in research simply refers to a person, place, thing, or phenomenon that you are trying to measure in some way. The best way to understand the difference between a dependent and independent variable is that the meaning of each is implied by what the words tell us about the variable you are using.

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Are There Other Important Variables To Know

Independent and dependent variables are the two most important variables to know and understand when conducting or studying an experiment, but there is one other type of variable that you should be aware of: constant variables.

Constant variables are simple to understand: they’re what stay the same during the experiment. Most experiments usually only have one independent variable and one dependent variable, but they will all have multiple constant variables.

For example, in Experiment 2 above, some of the constant variables would be the type of plant being grown, the amount of fertilizer each plant is given, the amount of water each plant is given, when each plant is given fertilizer and water, the amount of sunlight the plants receive, the size of the container each plant is grown in, and more. The scientist is changing the type of fertilizer each plant gets which in turn changes how much each plant grows, but every other part of the experiment stays the same.

In experiments, you have to test one independent variable at a time in order to accurately understand how it impacts the dependent variable. Constant variables are important because they ensure that the dependent variable is changing because, and only because, of the independent variable so you can accurately measure the relationship between the dependent and independent variables.

Which Variable Is The Experimenter Measuring

Keep in mind that the dependent variable is the one being measured. So, if the experiment is trying to see how one variable affects another, the variable that is being affected is the dependent variable.

In many psychology experiments and studies, the dependent variable is a measure of a certain aspect of a participant’s behavior. In an experiment looking at how sleep affects test performance, the dependent variable would be test performance.

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Where Do You Put Independent And Dependent Variables On Graphs

Independent and dependent variables always go on the same places in a graph. This makes it easy for you to quickly see which variable is independent and which is dependent when looking at a graph or chart. The independent variable always goes on the x-axis, or the horizontal axis. The dependent variable goes on the y-axis, or vertical axis.

Here’s an example:

As you can see, this is a graph showing how the number of hours a student studies affects the score she got on an exam. From the graph, it looks like studying up to six hours helped her raise her score, but as she studied more than that her score dropped slightly.

The amount of time studied is the independent variable, because it’s what she changed, so it’s on the x-axis. The score she got on the exam is the dependent variable, because it’s what changed as a result of the independent variable, and it’s on the y-axis. It’s common to put the units in parentheses next to the axis titles, which this graph does.

There are different ways to title a graph, but a common way is ” vs. “ like this graph. Using a standard title like that also makes it easy for others to see what your independent and dependent variables are.

Examples Of Independent And Dependent Variables In Experiments

Presentation of Data

Below are overviews of three experiments, each with their independent and dependent variables identified.

Experiment 1: You want to figure out which brand of microwave popcorn pops the most kernels so you can get the most value for your money. You test different brands of popcorn to see which bag pops the most popcorn kernels.

  • Independent Variable: Brand of popcorn bag
  • Dependent Variable: Number of kernels popped

Experiment 2: You want to see which type of fertilizer helps plants grow fastest, so you add a different brand of fertilizer to each plant and see how tall they grow.

  • Independent Variable: Type of fertilizer given to the plant
  • Dependent Variable: Plant height

Experiment 3: You’re interested in how rising sea temperatures impact algae life, so you design an experiment that measures the number of algae in a sample of water taken from a specific ocean site under varying temperatures.

  • Independent Variable: Ocean temperature
  • Dependent Variable: The number of algae in the sample

For each of the independent variables above, it’s clear that they can’t be changed by other variables in the experiment. You have to be the one to change the popcorn and fertilizer brands in Experiments 1 and 2, and the ocean temperature in Experiment 3 cannot be significantly changed by other factors. Changes to each of these independent variables cause the dependent variables to change in the experiments.

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Independent Vs Dependent Variable Key Takeaways

  • The independent and dependent variables are the two key variables in a science experiment.
  • The independent variable is the one the experimenter controls. The dependent variable is the variable that changes in response to the independent variable.
  • The two variables may be related by cause and effect. If the independent variable changes, then the dependent variable is affected.

How Do You Identify Variables In An Experiment

An easy way to think of independent and dependent variables is when youre conducting an experiment the independent variable is what you change and the dependent variable is what changes because of that. You can also think of the independent variable as the cause and the dependent variable as the effect.

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How To Remember Which Is Which

In order to try and remember which is the dependent variable and which is the independent variable, try putting them into a sentence which uses “causes a change in.”

Here’s an example. Saying, “light color causes a change in plant growth,” is possible. This shows us that the independent variable affects the dependent variable. The inverse, however, is not true. “Plant growth causes a change in light color,” is not possible. This way you know which is the independent variable and which is the dependent variable!

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Graphing The Independent Variable

GCSE Science Revision “Independent Variable, Dependent Variable, Control Variables”

When graphing data for an experiment, the independent variable is plotted on the x-axis, while the dependent variable is recorded on the y-axis. An easy way to keep the two variables straight is to use the acronym DRY MIX, which stands for:

  • Dependent variable that Responds to change goes on the Y axis
  • Manipulated or Independent variable goes on the X axis

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What Is A Standardized Variable In Biology

by Rachel Murdock / in Hobbies

In a biological experiment, there are several different variables that help a scientist discover new information. The independent variable is the aspect of the experiment that is changed or manipulated to find out an answer, while the dependent variable is the part of the experiment that is affected by the change in the independent variable. Standardised variables are those that are unaffected by the experiment.

Remembering Variables With Drymix

When results are plotted in graphs, the convention is to use the independent variable as the x-axis and the dependent variable as the y-axis. The DRY MIX acronym can help keep the variables straight:

D is the dependent variableR is the responding variableY is the axis on which the dependent or responding variable is graphed

M is the manipulated variable or the one that is changed in an experimentI is the independent variableX is the axis on which the independent or manipulated variable is graphed

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Independent Vs Dependent Variable

  • There can be many variables in an experiment, but the two key variables that are always present are the independent and dependent variable.
  • The independent variable is the one that the researcher intentionally changes or controls.
  • The dependent variable is the factor that the research measures. It changes in response to the independent variable or depends upon it.

Understand The Independent Variable In An Experiment

What is the independent variable on this graph?
  • Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
  • B.A., Physics and Mathematics, Hastings College

The two main variables in a science experiment are the independent variable and the dependent variable. Here’s the definition on independent variable and a look at how it’s used:

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Experiment : Simple Machines

Build and test a range of simple and complex machines with this K’nex kit. How does increasing a vehicle’s mass affect its velocity? Can you lift more with a fixed or movable pulley? Remember, the independent variable is what you control/change, and the dependent variable is what changes because of that.

Key Takeaways: Independent Variable

  • The independent variable is the factor that you purposely change or control in order to see what effect it has.
  • The variable that responds to the change in the independent variable is called the dependent variable. It depends on the independent variable.
  • The independent variable is graphed on the x-axis.

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Importance Of Control Variables

Remember, the independent variable is the one you change, the dependent variable is the one you measure in response to this change, and the control variables are any other factors you control or hold constant so that they cant influence the experiment. Control variables are important because:

  • They make it easier to reproduce the experiment.
  • The increase confidence in the outcome of the experiment.

For example, if you conducted an experiment examining the effect of the color of light on plant growth, but you didnt control temperature, it might affect the outcome. One light source might be hotter than the other, affecting plant growth. This could lead you to incorrectly accept or reject your hypothesis. As another example, say you did control the temperature. If you did not report this temperature in your methods section, another researcher might have trouble reproducing your results. What if you conducted your experiment at 15 °C. Would you expect the same results at 5 °C or 35 5 °C? Sometimes the potential effect of a control variable can lead to a new experiment!

Sometimes you think you have controlled everything except the independent variable, but still get strange results. This could be due to what is called a confounding variable. Examples of confounding variables could be humidity, magnetism, and vibration. Sometimes you can identify a confounding variable and turn it into a control variable. Other times, confounding variables cannot be detected or controlled.

What Is P A And B In Probability

Independent variable definition

There is a joint probability of p. There is a chance that event A and event B will occur. The intersection of two or more events is what it is referred to as. It is possible to write the probability of the intersection of A and B on a piece of paper. The probability of a card being a four and red is 2/52.

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What Is A Control Variable Definition And Examples

A control variable is any factor that is controlled or held constant during an experiment. For this reason, its also known as a controlled variable or a constant variable. A single experiment may contain many control variables. Unlike the independent and dependent variables, control variables arent a part of the experiment, but they are important because they could affect the outcome. Take a look at the difference between a control variable and control group and see examples of control variables.

Independent Vs Dependent Variables

The two main variables in an experiment are the independent and dependent variable.

An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable.

A dependent variable is the variable being tested and measured in a scientific experiment.

The dependent variable is ‘dependent’ on the independent variable. As the experimenter changes the independent variable, the effect on the dependent variable is observed and recorded.

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