Answer :
(B) 8
Explanation:
Given:
Mean, μ = 34
Standard deviation, σ = 9
Data points, x = 20, 22, 24, 28, 33, 35, 38, 40, 42, 45, 47
We can calculate the z score by the formula
[tex]z = \frac{x- u}{p}[/tex]
z(20) = [tex]\frac{20 - 34}{9} = -1.5[/tex]
z(22) = [tex]\frac{22-34}{9} = -1.3[/tex]
z(24) = [tex]\frac{24-34}{9} = -1.1[/tex]
z(28) = [tex]\frac{28-34}{9} = -0.6[/tex]
z(33) = [tex]\frac{33-34}{9} = -0.1[/tex]
z(35) = [tex]\frac{35-34}{9} = 0.1[/tex]
z(38) = [tex]\frac{38-34}{9} = 0.4[/tex]
z(40) = [tex]\frac{40-34}{9} = 0.6[/tex]
z(42) = [tex]\frac{42-34}{9} = 0.8[/tex]
z(45) = [tex]\frac{45-34}{9} = 1.2[/tex]
z(47) = [tex]\frac{47-34}{9} = 1.4[/tex]
Z score less than 0.7 is 8