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Psychology, Stress and the Immune system

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Aim: The researcher aimed to find out whether caffeine levels have any affect on reaction time. The researcher's experimental hypothesis is that higher caffeine levels will cause slower reaction times. The researcher's null hypothesis is that caffeine levels will have no effect on reaction times. Procedure: The researcher used an experimental method called a lab experiment and the experiment design that was used was an independent group design. The researcher used 15 participants from Ossett Sixth Form College that were attending their regular AS level Psychology class. The participants were aged between 16 and 17. The researcher used a technique known as an opportunity sample. Opportunity sampling is the sampling technique most used by psychology students. It consists of taking the sample from people who are available at the time the study is carried out and fit the criteria you are looking for. ...read more.


To be able to conduct this experiment properly the researcher used 15 participants, a caffeine free drink and a caffeinated drink, plastic beakers, a 30cm ruler and one researcher. Findings: The results were collected in a table. They show the results of the ruler test, this demonstrates the difference in reaction time between each group. Caffeine No Caffeine 5 11 30 6 20 4 18 4 8 6 5 4 8 17 8 From the results the researcher could create a table of central tendency. This includes the mean, mode and median. Caffeine No caffeine Mean 12.75 7.4 Mode 8 6 Median 8 4 These measures support the experimental hypothesis that was that the levels of caffeine will have an effect on reaction time. ...read more.


Random allocation to conditions means that there is no chance that the individuals will be able to fix the results. Investigator effect. This is a problem as the investigator could be biased and there for the results could be biased. E.g. the height of the ruler from hand when dropped. The ruler test could be conducted by an individual who has no worry about the outcome of the results. To make it fairer the investigator could measure the distance from the bottom of the hand to the ruler each time. Ruler test was conducted by the same person, which means there is less human error occurring. The amount of caffeine intake by each individual during the day was not controlled. This could cause the results to be insignificant. The experiment could be controlled over a 24 hour period. Causing the amount of caffeine intake controlled. Abigail Pratt and Nicky Griffiths ...read more.

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