{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

week4-confidence+intervals

# week4-confidence+intervals - #1.Sampleaccuracy theresearch...

This preview shows pages 1–5. Sign up to view the full content.

#1. Sample accuracy:  Researchers must have some sense of how good the sample must be to meet the objective to  the research.  Sample must be adequate for the task of making reasonably accurate generalization  about the population.  1

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

View Full Document
St a t i s t i c vs . Pa r a me t e r Sample Statistic Population Parameter Mean x μ (mu) Proportion p π (P) Standard Deviation s σ (sigma) s . e = σ/ n n= s a mpl e s i z e - St a nda r d de vi a t i on: s t a t i s t i c a l me a s ur e of popul a t i on he t e r oge ne i t y f or a qua nt i t a t i ve va r i a bl e - St a nda r d e r r or : t he de gr e e of e r r or i n a s a mpl e e s t i ma t e ; t he a ve r a ge a mount by whi c h a s a mpl e e s t i ma t e de vi a t e s f r om t he popul a t i on va l ue i t 2
Sa mpl e s i z e a nd St a nda r d Er r or Pr opor t i on va r i a bl e p = s a yi ng ye s q = s a yi ng no ( 1- p) - We don’ t know wha t r e a l π ( pa r a me t e r ) i s , but we t a ke a r a ndom s a mpl e of n. p = x/ n p i s t he numbe r of t hos e s a yi ng ye s ( x) i n t he s a mpl e , di vi de d by t he s a mpl e s i z e n. Ex. i f p=. 65 a nd we ha ve s a mpl e d n=1000, we f ound x=650 s a yi ng ye s . 3

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

View Full Document
St a nda r d Er r or We c a n’ t know t he pr e c i s e di f f e r e nc e be t we e n π a nd p be c a us e we don’ t know t he va l ue of π ( r e a l pe r c e nt
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 14

week4-confidence+intervals - #1.Sampleaccuracy theresearch...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online