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A researcher wishes to estimate the proportion of adults who have high-speed internet access. What size sample should be obtained if she wishes the estimate to be within 0.01 with 90% confidence if :

(a) she uses a previous estimate of 0.42?
(b) she does not use any prior estimates?

Respuesta :

zainsubhani

Answer:

Part A:

n=6591.87≅6592

Part B:

n=6765.06≅6765

Step-by-step explanation:

In order to calculate the sample size we use the following estimated Sample proportion formula:

[tex]n=p*q*\frac{Z^2}{E^2}[/tex]

Where:

p is the previous estimate

q is the 1-p

Z is the distribution

E is the margin

At 90% Confidence significance level is 0.1/2=0.05

Z at 0.05 or 5% =1.645

Part A:

p=0.42

q=1-p=1-0.42=0.58

Z=1.645

E=0.01

[tex]n=0.42*0.58*\frac{1.645^2}{0.01^2}[/tex]

n=6591.87≅6592

Part B:

Since no prior estimate is given we assume p =0.5 and q=0.5

[tex]n=0.5*0.5*\frac{1.645^2}{0.01^2}[/tex]

n=6765.06≅6765

Answer:

How did you decide o use 0.5?

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