11 - The actual reduction in heart attack occurrence went...

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

View Full Document Right Arrow Icon
1/21/11 Descriptive Statistics Ex: Range, Outliers, Percentiles, Poor Questions Most Common o Mean o Median o Mode Measure of Central Tendency- What are some general properties of this sample of data o Ex: not the tallest, or the shortest, but the most central height of the population Descriptive vs. Inferential Inferential- used to make inferences from your sample of data to the population as a whole Also used to infer whether the probability of differences between groups is reliable o Ex: A&M students have an average IQ of 115; TU students’ average score is 111 The averages are descriptive The question of whether that difference is reliable involves inferential statistics Difference of 4 points may be significant but not meaningful Aspirin Case o Aspirin has been shown to reduce heart attacks in cardiovascular patients by one fifth A significant effect As a result many physicians recommend it But what do the actual numbers – the descriptive statistics tell us?
Background image of page 1

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

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

Unformatted text preview: The actual reduction in heart attack occurrence went from 8.2% to 6.7% Is this meaningful? o IN people without cardiovascular disease aspirin reduces the chance of heart attack by one tenth Down from .57% to .51% This effect may be significant but the descriptive statistics gives a richer understanding of the meaningfulness. The Balance of Inferential and Descriptive Stats There is a need to consider both in order to determine how meaningful things really are The Effects of Positive Affect (from receiving candy) Article You will use both in your scientific reports Descriptive- Describe your data- usually central tendencies Inferential- Used to infer findings from your sample to the population o Whether or not your findings are reliable Next class- go into more details about descriptive statistics o Finish reading chapter 2 move on to chapter 3 if you want to get ahead...
View Full Document

Page1 / 2

11 - The actual reduction in heart attack occurrence went...

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