Question

A researcher wants to estimate, with 90% confidence, the proportion of people who use Instagram as their main social media. A previous study showed that 42% of those interviewed had a computer at their home. The researcher wishes to be accurate within 3% of the true proportion. How many people must the researcher survey? Show formula, substuon, a

Answer 1

Solution :

Given that,

= 0.42

1 - = 1 - 0.42 = 0.58

margin of error = E = 3% = 0.03

At 90% confidence level

= 1 - 90%  

= 1 - 0.90 =0.10

/2 = 0.05

Z/2 = Z0.05 = 1.645 ( Using z table )

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

= (1.645 / 0.03)2 * 0.42 * 0.58

=732.43

Sample size = 733