Question

Question 710 points A study by Albitare Insurance Co finds that not oftengers have used cellphones while driving (The Wall Street Journal May, 2010L S e a random sample of 100 teen drivers is taken. What is the probability that the sample proportion is less than 0.80 1.0.82 II 0.52 III 0.965 IV.0.30

Answer 1

7)

Solution :

$\sigma$_{$\hat p$} =  $\sqrt$[p ( 1 - p ) / n] =  $\sqrt$ [(0.82 * 018) / 100 ] = 0.03842

P( $\hat p$ < 0.80) =

= P[( $\hat p$ - $\mu$ _{$\hat p$} ) / $\sigma$ _{$\hat p$} < (0.80 - 0.82) / 0.03842]

= P(z < -0.52)

= 0.30

Option IV