In: Statistics and Probability
A study of homeless men in the city revealed that out of 242 selected to be interviewed, 65 had been employed within the last year. Provide a 95% confidence interval for the proportion of all homeless men who had been employed within the past year. Interpret your result.
GIVEN:
Size of homeless men in the city
selected to be interviewed 
Number of homeless men who are
employed within the last year 
FORMULA:
The formula for 95% confidence interval for population proportion is,

where
is the z
critical value at 95% confidence level.
CRITICAL VALUE:
The two tailed z critical value at
95% confidence level is
.
CALCULATION:
The sample proportion is given by,



The 95% confidence interval for the proportion of all homeless men who had been employed within the past year is,




The 95% confidence interval
for the proportion of all homeless men who had been employed within
the past year is
.
Thus we are 95% confident that the true proportion of all homeless
men who had been employed within the past year lies between 0.2127
and 0.3245.