Question
In: Statistics and Probability
If you want to be 95% confident of estimating the population proportion to within a sampling...
If you want to be 95% confident of estimating the population proportion to within a sampling error of ±0.02 and there is historical evidence that the population proportion is approximately .35, what sample size is needed?
Solutions
Expert Solution
Solution :
Given that,
=
0.35
1 -
= 1 - 0.35 = 0.65
margin of error = E = % = 0.02
At 95% confidence level the z is ,
= 1 - 95% = 1 - 0.95 = 0.05
/ 2 = 0.05 / 2 = 0.025
Z/2
= Z0.025 = 1.96 ( Using z table ( see the 0.025 value in standard
normal (z) table corresponding z value is 1.96 )
Sample size = n = (Z
/2
/ E)2 *
* (1 -
)
= (1.96 / 0.02)2 * 0.35 * 0.65
= 2184.91
Sample size = 2185
orchestra answered 3 years agoRelated Solutions
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