One aspect of this is the reliability , validity , and accuracy of the experiment. So what do these terms mean and how do these things affect each other? An experiment is a set of measurements that are analysed to test a link or relationship between different things.
The measurements are usually analysed in an experimental report, which is set out in a clear format to help the reader understand different aspects of the experiment, like the aim, the equipment and method used, the results obtained, how they were analysed, and what conclusions can be drawn. When writing the method of an experiment, you must ensure that each step of the method incorporates reliability, accuracy or validity. Validity relates to the experimental method and how appropriate it is in addressing the aim of the experiment:.
Several aspects of the experiment can contribute to validity: the equipment, the experimental method, and the analysis of the results. Although it may seem obvious, the appropriate equipment needs to be used. The equipment must be suitable for carrying out the experiment and taking the necessary measurements. The experiment is ultimately testing a relationship between cause and effect: how changing X affects Y.
To address this, you must only change X, and see what happens to Y. If you allow other changes at the same time, then you cannot make a valid conclusion about how X affected Y, since Y may have been affected by the other changes as well. The correct way to describe this is in terms of the independent, dependent, and control variables.
The independent variable in an experiment is the one you set X. The dependent variable is the one you measure Y, because it depends on X. All other variables are called control variables, and they must be kept constant to prevent them from affecting the dependent variable. This forms part of the experimental method. The method including the analysis may contain some assumptions that need to be satisfied, e.
The experimental method must ensure that all the assumptions are satisfied, otherwise, you will end up using a method or analysis that is inappropriate, and the result will be invalid.
You may be able to identify invalid measurements and discard them from the analysis. If your experiment is invalid, then the result is meaningless because either the equipment, method or analysis were not appropriate for addressing the aim. Reliability is about how close repeated measurements are to each other. You can consider the reliability of a measurement, or of the entire experiment. A measurement is reliable if you repeat it and get the same or a similar answer over and over again, and an experiment is reliable if it gives the same result when you repeat the entire experiment.
You can test reliability through repetition. Jump to main content Jump to main menu Jump to top menu. Print Friendly Page. Recommended by:. What's your opinion? Average rating Current rating: 2. Read comments [ Comment awaiting moderator's approval Bookmark this page. Poll Which percentage of your results is within 1cm of the mean?
MENU 1: Home. Print Friendly Page Recommended by:. Validity Validity describes whether the results of an experiment really do measure the concept being tested. Accuracy Accuracy describes how well a measuring instrument determines the variable it is measuring.
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