Getting The Confidence Intervals For Proportions

By Essie Osborn


Statistics define confidence interval as a range of figures that gives the most approximate answer. The estimations of computations are important in determining the reliability the data. The answer should be the same if the experiment is repeated using similar parameters. The research is more reliable if similar results would be obtained.

The central limit theorem has been used to calculate the figure instead of approximation. Confidence intervals for proportions show how much the results can be used in decision making about the population. A large sample makes it easy to attain a hundred percent accuracy. The samples must, however, have been taken evenly across the population if accurate results are to be obtained.

Probability distribution and normal distribution should give figures that are close. This increases the chances of accuracy. The central limit theorem works best where 0 represents a false figure and 1 represents a true figure. Figures below and above zero make it easy to work with. The positive and negative approach simplifies the calculation.

Finding a research with negative figures is sometimes very difficult. This has made the use of the theorem a bit challenging. The method is, however, effective when working with extrapolations. Use of binomial approach will work with many cases.

The confidence interval is given as a percentage. Using a larger population sample makes it possible to obtain an accurate figure. A lesser figure is likely to indicate that too many assumptions were made such that the results cannot be accurate. Conclusions based on this figure are likely to be erroneous.

The interval for a mean indicates a value within which the real figure must lie. It tests the reliability of an estimate. If the value lies outside the bounds set, the research is regarded as doubtful. Such an interval is used in different fields including business and medicine.

A wide interval might suggest that the data collected is not sufficient for the conclusion being sort. The figures are unreliable and do not work well with the research methodology. Such data cannot give a conclusive answer and any that is given would be very erroneous.

Estimates give rough ideas of the expected results when computations are complete. Binomial method gives figures that are more reliable and accurate. An increased size of the sample means that accuracy levels are raised and reliable.

The data collected should be linear and representative of the population. Linear arrangement shows areas where discrepancies can be sited and therefore points at possible errors in collection. Statistic classes and books have fronted this as a reliable method. Smaller figures are easy to approximate. This is not always the case since some of the surveys end up with very large figures.

The methods used range from Clopper Pearson Interval, Jeffreys interval and Wilson score interval approaches. Others are Arc Sine transformation and Agresti Coull methods that are known for the reliability of their values. The discrepancies in the figures obtained largely depend on assumptions and accuracy of data collected.




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