slide 27 chapter 7
p hat = 17/987 = 0.017
slide 28
99 percert CI = 12 = .99 = alpha/2 = .005
z* = Z alpha/2 = Z.005
= 2.58
99% Confindence interval = (p hat +or Z* (square root of p hat (1 p hat)/ n)
n= 987 and p hat = .017
so 0.017 plus or minus 2.58 x (square root 0.017 (10.017)/987))
= 0.017 plus or minus 0.011
= .006 , .0028
smaller number left bigger number to the right
we are 99 percent confident that the true pop perportion falls between .006 and .0028
Slide 30:
x bar is a sample mean, must know sigma to use this formula
slide 31 population distrubition x follows N ( meuw, sigma)
N stands for normal population.. then
x bar follow N (meuw, sigma/ square root of n)
if X is not Normal then By Central limit therom n is greater then 30 then x bar = N (meuw x .
sigma x/ squeare root of n).
x bar means
Slide 32 important that is normal with stardanrd deviation
Slide 33
:
90 percent CI
1 alpha = .90 then alpha/2 = .05
Z* = Z.05 = 1.645
n =10 sigma = 3
xbar = 23.3 + 27.9 + 26.1 /10=
90% CI= xbar plus or minus Z.05 x( 6/sq root of n)
= 25.36 plus or minus 1.645 x (3 / squeare root of 10)= 25.36 plus or minues 1.56
= (23.8, 26.92) must integrate we are 90 percent confindent that the true av miles per gallon is bt
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 Fall '07
 LRLink
 Microbiology, Standard Deviation, xbar, sq root

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