(a) What is the minimum sample size needed assuming that no prior information is available? n= ______ (Round up to the nearest whole number as needed.) (b) What is the minimum sample size needed using a prior study that found that 26% of the respondents said they think their president can control the price of gasoline? n= ______ (Round up to the nearest whole number as needed.)
A researcher wishes to estimate, with 99% confidence, the population proportion of adults who think the president of their country can control the price of gasoline. Her estimate must be accurate within 4% of the true proportion.
a) No preliminary estimate is available. Find the minimum
b) Find the minimum sample size needed, using a prior study that found that 26% of the respondents said they think their president can control the price of gasoline.
c) Compare the results from parts (a) and (b).
(a) What is the minimum sample size needed assuming that no prior information is available?
n= ______
(Round up to the nearest whole number as needed.)
(b) What is the minimum sample size needed using a prior study that found that 26% of the respondents said they think their president can control the price of gasoline?
n= ______
(Round up to the nearest whole number as needed.)
Margin of error = 0.04
z-critical value at alpha(0.01) = 2.576
The sample size is given by
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