 Wysłany: Śro 10:03, 09 Mar 2011 Temat postu: measure of variability = square root of [ |
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| y“measure of variability” which is called the
stan- dard error of the difference in two means.In other words: measure of variability = square root of [(SEM1)2+ (SEM2)2] 4.A 95% con?dence interval for the difference in the two population means is difference in sample means ±2 ×measure of variability or difference in sample means ±2 ×square root of [(SEM1)2+(SEM2)2] This format was based on the fact that the “sample value” over repeated samples was predicted to follow a bell-shaped curve centered on the “population value.” All we needed to know in addition was the “standard deviation” for that speci?c bell-shaped curve. The same is true for calculating the difference in two means. Here is the recipe you follow: A DIRECT COMPARISON OF DIET AND EXERCISE We are now in a position to compute a 95% con?dence interval for the difference in population means for weight loss from dieting only and weight loss from exer- cising only. Let’s follow the steps outlinedusing the data from the previous section: Steps 1 and 2pute sample meansstandard deviationsand SEMs: Diet OnlyExercise Only sample mean = 7.2 kgsample mean = 4.0 kg sample standard deviation = 3.7 kgsample standard deviation = 3.9 kg number of participan christian louboutin pumpyilai: nike high heels nike heels for women louis vuitton outlet http://leetstreams.com/profile_blogs/yixian005/&action=view&id=193098 |
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