Question

Chi square help.....Metal given

Answer 1

Chi-square tests are nonparametric tests that examine nominal categories as opposed to numerical values. Consider a situation in which you may want to transform numerical scores into categories. Provide a specific example of a situation in which categories are more informative than the actual values.

Take an example of a hypothesis from a parametric test that you worked on earlier in this course, such as an analysis of variance (ANOVA) or a t-test. Explain what changes would be required so that you could analyze the hypothesis using a chi-square test. For instance, rather than looking at test scores as a range from 0 to 100, you could change the variable to low, medium, or high. What advantages and disadvantages do you see in using this approach? Which is the better option for this hypothesis—parametric approach or nonparametric approach?

Answer 2

An example for numerical to categorical data off the top of my head: Light of different color has different wavelengths, but certain ranges of wavelengths qualify as certain shades/hues/tints/etc.

You can generalize and say a certain range can be called "blue" or "red". Red is usually attributed to light that has a wavelength between 780 and 622 nanometers, whereas blue light is between 492 and 455 nm. (source: http://www.livephysics.com/physical-constants/optics-pc/wavelength-colors/ )

To the average (physics-deprived) person, "red" and "blue" obviously mean more than a given wavelength of light, so a categorical/qualitative description might be of more use in such a context.

Another example would be grading scales. Certain ranges of scores will qualify as an A, a B, and so on. Suppose you want to examine the grades of high school students admitted into a prestigious university. Students that fall in the A/B range tend to have a better chance of being admitted, while those at the other end of the spectrum are "significantly" less likely to enroll. ("Significant" here can take on either the statistical or colloquial meaning of the word. The former could be established with an actual statistical test.)

Answer 3

thanks