Weighted Mean Calculation using HP 12C Statistics Calculator, Notas de estudo de Engenharia Mecânica

Baixe Weighted Mean Calculation using HP 12C Statistics Calculator e outras Notas de estudo em PDF para Engenharia Mecânica, somente na Docsity! hp calculators HP 12C Statistics - Weighted mean Weighted mean HP12C weighted mean Practice finding average price sales Practice finding averages and standard deviations with two variables hp calculators HP 12C Statistics - weighted mean hp calculators - 2 - HP 12C Statistics - weighted mean - Version 1.0 Weighted mean Statistics can be understood as a set of tools that involves the study of methods and procedures used for collecting, classifying, and analyzing data. Statistical tools also offer the means for making scientific inferences from such resulting summarized data. In a simple average, the individual values are added together and divided by the number of values involved. In effect, each value's weight or contribution to the average is 1/n, where n is the number of values in the sample. Comparatively, a weighted mean is an average computed by giving different weights to some of the individual values. For example, a simple average of the three numbers 5, 10 and 15 applies an equal weight (1/3) to each value and the resulting average is 10. A weighted mean or average might apply a weight of 50% to the 5 and 25% to each of the 10 and 15, resulting in a weighted average of 8.75. There are many situations where a weighted average computation saves a great deal more time than using a simple average approach. More generally, given a set of collected data where repeating values vn occur kn times (weight), the weighted mean is computed as: ( ) ∑ ∑ ×= n nn k vk xω Figure 1 HP12C weighted mean On the HP12C, statistics data are stored as a set of summations resulting from the originally collected data. The collected data set must be typed in prior to using any statistics features available in the HP12C because all statistics functions use values produced during the summations. The weighted mean is computed with the use of the gc key and the contents of two of the summations are used. ∑ ∑= w wx xω Figure 2 where: x is the repeating value w is the number of occurrences of x (weight) xω is the weighted mean Practice finding weighted mean of sale prices Example 1: A big mall wants to know the weighted mean of the sales price of 2,000 units of one product that had its final price adjusted according to the first ten days of sales. The table below summarizes the relation between final price and number of sold units.