Question

A researcher wishes to​ estimate, with

9090​%

​confidence, the population proportion of adults who eat fast food four to six times per week. Her estimate must be accurate within

55​%

of the population proportion.

​(a) No preliminary estimate is available. Find the minimum sample size needed.

​(b) Find the minimum sample size​ needed, using a prior study that found that

2222​%

of the respondents said they eat fast food four to six times per week.

​(c) Compare the results from parts​ (a) and​ (b).

​(a) What is the minimum sample size needed assuming that no prior information is​ available?

nequals=nothing

​(Round up to the nearest whole number as​ needed

Answer 1

a)

here margin of error E =	0.050
for90% CI crtiical Z          =	1.645
estimated proportion=p=	0.500
required sample size n =	p*(1-p)*(z/E)2=	271.00

b)

here margin of error E =	0.050
for90% CI crtiical Z          =	1.645
estimated proportion=p=	0.220
required sample size n =	p*(1-p)*(z/E)2=	186.00

c) Knowing an estimate reduce requirement of sample size,