An Instrument - Reliable and Validity Assignment

An Instrument - Reliable and Validity - Assignment Example A measurement may be reliable but need not be valid. Nevertheless, measurement has to be reliable before it can be valid. A tool should be reliable and should be suitable for measuring the intended object. In designing a research project it is absolutely necessary that the measurements are both reliable and valid. If it is not so the tools of measurement are basically useless for measuring what the researcher wanted to measure. 2. Almost daily, we hear about research that seems to contradict earlier findings. One day, for example, a particular food is good for you and the next it is not. What does this reflect about the scientific method What are the advantages and disadvantages of the scientific method It is very true that we find research to support or to conclusively oppose something. For any study that puts forward a recommendation, there is another one that is apparently researched and documented and challenging the conclusions of the first. There is no convergence in the points of view of people. This does not invalidate the scientific method. There could may many possibilities for this divergence. Perhaps a researcher may not have used the valid tools for testing. The tools themselves may not have been reliable. The test conditions may not have been the same in all cases.   It insists on systematic experimentation. Scientists have developed criteria and practices to reduce the individual and social bias on scientific findings. The basic approach is an experiment, observation, and inference. It approaches reality objectively. However, our five senses might even play tricks on us. That is why theories of Ptolemy were later replaced by the theories of Copernicus. Some times more efficient tools to observe reality will be developed which give more data, hitherto unavailable. The use of an electron microscope has unraveled new insights into cell and modern cell biology is entirely different from what it was fifty years ago. 3. Suppose you wish to measure the effect of physical exercise on self-esteem. What type of experimental design would be most appropriate to Describe the types of groups necessary for this design? How would you measure your variables Which threats to internal validity would you need to consider The available evidence indicates that exercise not only benefits by providing a healthier body but also enhancing self-esteem. However, this has to be proved by empirical evidence. Visitors to a fitness center would be the ideal group to test the validity of this thesis.