Question

Use the given data to find the minimum sample size required to estimate a population proportion or percentage. Margin of​ error: two percentage​ points; confidence level 90​%; from a prior​ study,

Modifying Above p with care tp is estimated by the decimal equivalent of 38​%

n=________________

​(Round up to the nearest​ integer.)

Answer 1

Solution:

Given that,

= 38% = 0.38

1 - = 1 - 0.38 = 0.62

margin of error = E = 2% = 0.02

At 90% confidence level the z is ,

= 1 - 90% = 1 - 0.90 = 0.10

/ 2 = 0.10 / 2 = 0.05

Z_/2 = Z_0.05 = 1.645

Sample size = n = ((Z _{/ 2}) / E)² * * (1 - )

= (1.645 / 0.02)² * 0.38 * 0.62

= 1593.84

= 1594

n = sample size = 1594