Answers to Questions (Experiment 1)

ANSWERS TO QUESTIONS (EXPERIMENT 1)

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1. Give the significance of Grubbs test.

The Grubbs test is an important method in identifying outliers. Identifying outliers requires an objective criterion and Grubbs test makes use of objective information such as the mean, the questionable measurement, standard deviation, and tabulated critical g values. It quantifies how far an outlier is from the others and then compares the ratio obtained from critical g values. Rejecting or accepting outliers cannot be done objectively by just guess work, and so Grubbs test is significant in a way that it ensures that data omission is done objectively.

2. Give the significance of mean and standard deviation.

The mean is a measure of central tendency and it shows the average value in the data while the standard deviation shows the spread of the data. The importance of knowing the average of the data is that you get the picture of what most the data is like. This is, though, gullible to outliers. This is where standard deviation comes in, it shows how diverse the data set is. Without standard deviation, you can’t get a handle on whether the data are close to the average or whether the data are spread out over a wide range.

3. Give the significance of the confidence interval.

Confidence interval provides a range of values within which the population mean is expected to lie at a specified confidence level. The boundaries of the confidence interval are termed as confidence limits. Confidence intervals provide an ‘estimate interval’, that is, a range of values around the point estimate within which the true value can be expected to fall. The wider the confidence interval is, the more variability in the sample, and the less precise the point estimate.

4. How do the statistics calculated from data set 1 differ from those obtained from data set 2?

The mean computations for data set 1 and data set 2 are not far from each...