In 20 packages of Doggy Meat Snacks there were 66 lamb snack

In   20   packages of “Doggy Meat Snacks” there were   66   lamb snacks. The total number of snacks in the   20   bags was   110 . We wish to calculate a   90%   confidence interval for the population proportion of lamb snacks.

Which distribution should you use for this problem?  (pick one) Binomial Normal Uniform Poisson

The sample proportion is

p= _______

The critical value   zcrit   of the standard normal distribution for the 90% confidence interval is

zcrit= ________

The standard error for   p   is

standard error = ________

The error bound for the proportion (EBP) is

EBP = _________

The confidence interval is given by   (L,U) , where

the lower bound is   L= _____ and the upper bound is   U= _______

Note: The computed   L   may be   <0 , and the computed   U   may be   >1 . Enter these in any case.

Solution

Normal distribution

p = 66/110 = 0.6

critical value for alpha = 1 - 0.90 = 0.10

alpha/2 = 0.05

critical Z = +/- 1.64

Standard error = srqt ( 0.6*0.4/110) = 0.0467

errror bound 0.6 +/- 1.64 * 0.0467

0.6 +/- 0.0766

lower bound = 0.5234

upper bound = 0.6766