Question

Up to 20% of people in the United States will catch the flu this year. Use this figure as the population mean, and assume you work in an office space with 30 coworkers: b. What's the standard deviation? c. Using the appropriate approximation, determine Px > 1), that is, the probability that more than one of your coworkers will get the flu this year.

Answer 1

Solution:-

a) The expected number of coworkers to get the flu this year is 6.

E(x) = n*p

E(x) = 30*0.20

E(x) = 6.0

b) The standard deviation is 2.1909.

$\sigma =\sqrt{n\ast p(1-p)}$

$\sigma =\sqrt{30\ast 0.20(1-0.20)}$

$\sigma = 2.1909$

c ) The probability that more than one of your coworkers will get the flu this year is 0.9888.

x = 1

By applying normal distribution:-

$z = \frac{x-\mu }{\sigma }$

z = - 2.282

P(z > -2.282) = 0.9888