Question

The proportion of drivers who use seat belts depends on things like age, gender, and ethnicity. As part of a broader study, investigators observed a random sample of 121 female Hispanic drivers in Boston. Suppose that in fact 66% of all female Hispanic drivers in the Boston area wear seat belts. In repeated samples, the sample proportion  p^ would follow approximately a Normal distribution.

What is the standard deviation of p^ ? (Enter your answer rounded to four decimal places.)

standard deviation:

Answer 1

Solution

Given that,

p = 0.66

1 - p = 1-0.66=0.34

n = 121

= p =0.66

standard deviation= =  [p ( 1 - p ) / n] =   [(0.66*0.34) / 121 ] = 0.0431

standard deviation= =0.0431