Stats Exam 2

Stats Exam 2 - sample mean: When most people use the word...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
sample mean: When most people use the word average, they are talking about the mean. where is the sample meanis the sumis the data valuesis the sample size The mean is the sum of the data values divided by the sample size.Important characteristics of the mean are below:is sensitive to extreme scoresis not necessarily a possible value sample median: the middle scoreProcedure for calculating (denotes the sample median) follows: rank data from smallest to largest, if n is odd, median is the middle score, if n is even, median is the average of two middle scores, Important characteristics of the median are below: is not sensitive to extreme scores, exactly half of the data is below and exactly half of the data is above Because of the characteristics of the mean and median, if extreme scores exist in a data set the median is a better measure of central tendency.If extreme scores are unlikely, the mean varies less from sample to sample than the median and is a better measure. sample mode: the most frequent score. There are some major weaknesses with the mode. Notice changing one value totally changes the mode making it unstable. The one advantage of using the mode is that it can be used for qualitative data and that is when it should be used. The mean or median cannot be used for qualitative data. A measure of dispersion is a measure of the spread of the data points or we can also say a measure of how much variability there is in the data set. The most common way to numerically describe a data set is with a measure of center and a measure of dispersion. sample range: Represents the distance between the high and low value. range = high score - low score. Important characteristics of the range are below: easy to compute, totally sensitive to extreme scores, not a good measure of dispersion in most cases sample variance: measures the average squared distance the data values are from whereis the sample varianceis the sum is the data values is the sample meanis the sample size Notice there are two ways to calculate . The first way is the conceptual formula and you can see that this equation comes straight from the definition. The second equation is the algebraic equivalent of the first and is the one I suggest you use when calculating variance
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 07/12/2011 for the course STATS 200 taught by Professor Bradley,w during the Fall '10 term at KCTCS.

Page1 / 3

Stats Exam 2 - sample mean: When most people use the word...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online