Homework SourseA researcher wishes to estimate with 90 confidence the propo
A researcher wishes to estimate, with 90% confidence, the proportion of adults who have high speed internet access. Her estimate must be accurate within 4% of the true proportion.
A) find the minimum sample size needed, using a prior study that found that 54% of the respondents said they have high speed internet.
B) no preliminary estimate is available. Find the minimum sample size needed.
A researcher wishes to estimate, with 90% confidence, the proportion of adults who have high speed internet access. Her estimate must be accurate within 4% of the true proportion.
A) find the minimum sample size needed, using a prior study that found that 54% of the respondents said they have high speed internet.
B) no preliminary estimate is available. Find the minimum sample size needed.
A) find the minimum sample size needed, using a prior study that found that 54% of the respondents said they have high speed internet.
B) no preliminary estimate is available. Find the minimum sample size needed.
Solution
a)
Compute Sample Size ( n ) = n=(Z/E)^2*p*(1-p)
Z a/2 at 0.1 is = 1.64
Samle Proportion = 0.54
ME = 0.04
n = ( 1.64 / 0.04 )^2 * 0.54*0.46
= 417.5604 ~ 418
b)
Compute Sample Size ( n ) = n=(Z/E)^2*p*(1-p)
Z a/2 at 0.1 is = 1.64
Samle Proportion = 0.5
ME = 0.04
n = ( 1.64 / 0.04 )^2 * 0.5*0.5
= 420.25 ~ 421
