The probability that Phil will walk to work is 0.1. The last 20 days that Phil went to work are examined. Determine the mean and variance of the number of days that Phil walked to work in the last 20 working days.?

From the given data

n= 20,p=0.1

Finding the value of q

q = 1-p
q = 1-0.1 ⇒ q=0.9

Mean \$\mu\$ = np

\$\mu\$

20 × 0.1

Mean \$\mu\$

2

Variance \$\sigma^2\$ = npq

\$\sigma^2\$

20 × 0.1 × 0.9

Variance \$\sigma^2\$

1.8

Mean and variance of the number of days that Phil walked to work in the last 20 working days

\$\mu\$ = 2

\$\sigma^2\$ = 1.8

Answer

B