Question:
A random sample of $170$ boys from $8502$ boys in an area showed that $21$ had some nutritional deficiency. Give confidence interval , proportion of nutritionally deficient boys and standard error of estimate .
Here , $P’ = \frac nx = \frac {21}{170}$
$Q’ = 1-p’ = \frac {170-21}{170}$
But as per proportion formula : $P'\pm Z_{ (\frac{\alpha}2)}* \sqrt{(\frac{P'Q'}N)}$
In this question there is no confidence interval because of which I am unable to find the value of $Z_{(\frac {\alpha}2)}$ . Please suggest how to proceed hereafter. I am stuck.