Stat 1053-10 informal notes 10-19-12 - HW for credit is due...

HW for credit is due in discussion next week (10/23).
Recall
Formula for large-sample CI for μ (Section 7.2)
100(1- α)% CI for μ is
(- z
α/2
σ , + z
α/2
σ ),
where z
α/2
is a value from the Z-table, is the sample
mean, and σ= σ/ (√n).
Note: , σ, and n come from the word problem;
you have to get z
α/2
from the Z-table, using
confidence coefficient (1- α).
(- z
α/2
σ , + z
α/2
σ ) =
(- z
α/2
σ/ (√n) , + z
α/2
σ/ (√n) ) uses the population sd
σ.
If the population sd σ is not known, use the sample
standard deviation s (Chapter 2) instead; the CI
formula becomes
(- z
α/2
s/ (√n) , + z
α/2
s/ (√n) ).

Large sample confidence interval (CI) for p (Section
7.4)
Background: binomial type situation – have
successes and failures, eg, household tunes in to a
show or does not.
Population proportion p,
Sample proportion (from a sample of size n)