Question

Translate the statement into confidence intervals. Approximate the level of confidence.

In a survey of 1062 in a country 78% said being able to speak the language is at the core of national identity . The surveys margin of error is +-3.9%.

The confidence interval for the proportion is (?,?)

Answer 1

Solution :

Given that,

n = 1062

Point estimate = sample proportion = = 0.78

1 - = 0.22

Margin of error = E = 0.039

A 95% confidence interval for population proportion p is ,

- E < p < + E

0.78 - 0.039 < p < 0.78 + 0.039

0.741 < p < 0.819

The confidence interval for the population proportion p is : (0.741 , 0.819) or (74.1% , 81.9%)