Why do replicates in an experiment

If you are trying to create a prediction model, multiple replicates can increase the precision of your model.

If you have more data, you might be able to detect smaller effects or have greater power to detect an effect of fixed size. Your resources can dictate the number of replicates you can run. For example, if your experiment is extremely costly, you might be able to run it only one time. Example of replicates and repeats A manufacturing company has a production line with a number of settings that can be modified by operators.

The first experiment uses repeats. The operators set the factors at predetermined levels, run production, and measure the quality of five products. They reset the equipment to new levels, run production, and measure the quality of five products. They continue until production is run one time at each combination of factor settings and five quality measurements are taken at each run.

The second experiment uses replicates. The operators set the factors at predetermined levels, run production, and take one quality measurement. They reset the equipment, run production, and take one quality measurement. In random order, the operators run each combination of factor settings five times, taking one measurement at each run.

Nov 26, Explanation: The replication is so important in science. Mar 20, Scientists must replicate experiments to ensure validity and account for error.

Explanation: Suppose you tested the effectiveness of your new medicine by giving it to one person and their symptoms cleared up. Related questions How do I determine the molecular shape of a molecule? What is the lewis structure for co2? What is the lewis structure for hcn? How is vsepr used to classify molecules? What are the units used for the ideal gas law? For example, imagine that health psychologists perform an experiment showing that hypnosis can be effective in helping middle-aged smokers kick their nicotine habit.

Other researchers might want to replicate the same study with younger smokers to see if they reach the same result. When studies are replicated and achieve the same or similar results as the original study, it gives greater validity to the findings. When conducting a study or experiment , it is essential to have clearly defined operational definitions. In other words, what is the study attempting to measure? When replicating earlier researchers, experimenters will follow the same procedures but with a different group of participants.

So what happens if the original results cannot be reproduced? Does that mean that the experimenters conducted bad research or that, even worse, they lied or fabricated their data? In many cases, non-replicated research is caused by differences in the participants or in other extraneous variables that might influence the results of an experiment.

For example, minor differences in things like the way questions are presented, the weather, or even the time of day the study is conducted might have an unexpected impact on the results of an experiment. Researchers might strive to perfectly reproduce the original study, but variations are expected and often impossible to avoid. In , a group of researchers published the results of their five-year effort to replicate different experimental studies previously published in three top psychology journals.

The results were less than stellar. As one might expect, these dismal findings caused quite a stir. So why are psychology results so difficult to replicate? Writing for The Guardian , John Ioannidis suggested that there are a number of reasons why this might happen, including competition for research funds and the powerful pressure to obtain significant results.

There is little incentive to retest, so many results obtained purely by chance are simply accepted without further research or scrutiny. The project authors suggest that there are three potential reasons why the original findings could not be replicated. The Nobel Prize-winning psychologist Daniel Kahneman has suggested that because published studies are often too vague in describing methods used, replications should involve the authors of the original studies in order to more carefully mirror the methods and procedures used in the original research.

While some might be tempted to look at the results of such replication projects and assume that psychology is rubbish, many suggest that such findings actually help make psychology a stronger science.

Human thought and behavior is a remarkably subtle and ever-changing subject to study, so variations are to be expected when observing diverse populations and participants. Some research findings might be wrong, but digging deeper, pointing out the flaws, and designing better experiments helps strengthen the field.