The independent variable (<em>action of the disinfecting sprays Clorox and Lysol</em>) always produces a change in the dependent variable (<em>Germ survival or growth</em>). However, the control variable produce no changes on the results (<em>temperature, light exposure, time</em>). You state a hypothesis to predict what is goint to occur (<em>Clorox is more efficient in desib¡nfecting surfaces than Lysol</em>).
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During an experiment, the researcher applies different treatments to the experimental groups to analyze their response. It is also useful to have a control group to observe how it responds when no treatment is applied. In these situations, the researcher compares three groups: a control group and two experimental groups. All the groups are identical in all aspects except for the independent variables.
- The control group is used to identify any other factors influencing the results obtained in the study, apart from the modified variables of the treatment. The <em>independent variable keeps constant in the control group. </em>
- The experimental group receives the treatment. The researcher voluntarily changes the values of the independent variable to observe how it affects the dependent variable.<em> There can be several experimental groups.</em>
- Independent (manipulated) variable: <em>Refers to all the variables in an experiment that provoke a response in another variable.</em> An independent variable is the one that changes or is modified to analyze its <em>effects </em><em>on another variable</em>. The researcher changes on purpose the independent variable to observe the response of the dependent variable.
- Dependent variable: Refers to the variable, <em>which response </em><em>depends</em><em> on any change in the </em><em>independent variable</em><em>.</em> It represents a quantity of something which value depends on how the independent variable is modified. The change in the dependent variable might be <em>proportional or inversely proportional </em>to the change in the manipulated variable.
- Controlled variables are kept constant in the control groups and the experimental groups. Unlike the independent variable, the controlled variables do not influence the results. These variables do not affect the response of the dependent variable.
⇒ The independent variable → Action of the disinfecting spray Clorox and Lysol
⇒ The dependent variable → Germ survival
⇒ The controlled variables → Environmental temperature, light exposure, time.
To confirm that the experiment is working we just need to compare periodically the three petri dishes to see how microorganisms are growing, if they are.
Hypothesis: Clorox is more efficient in desib¡nfecting surfaces than Lysol.
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Related link: brainly.com/question/24468408