According to a college survey 22 of all students work full t

According to a college survey, 22% of all students work full time. Find the standard deviation for the random variable X, the number of students who work full time in the sample size of 16.

A) 2.75 B)1.98 C)1.88 D) 3.52 E) 1.66

The answer is E but why? what is the formula?

Solution

s = standard deviation = sqrt(np(1-p))

As n = 16, p = 0.22,

= sqrt(16*0.22*(1-0.22))

= 1.656985214

= 1.66 [ANSWER]