Question 1043432
A researcher wishes to​ estimate, with 90​% ​confidence, the population proportion of adults who are confident with their​ country's banking system. His estimate must be accurate within 3​% of the population proportion.
​(a) No preliminary estimate is available. Find the minimum sample size needed.
n = [1.645/0.03]^2*0.5^2 = 752 when rounded up
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​(b) Find the minimum sample size​ needed, using a prior study that found that 24​% of the respondents said they are confident with their​ country's banking system.
n = [1.645/0.03]^2*0.24*0.76 = 549 when rounded up
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​(c) Compare the results from parts ​(a) and ​(b).
With (b) you have more information to use to get
the estimate so your sample can be smaller.
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Cheers,
Stan H.
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