Question

Help with probability please?

Answer 1

Answer:

1.)

Number of passengers who are 6 years old $=\frac{1}{2}$

Number of passengers who are 7 years old $=\frac{1}{10}$

Number of passengers who are 8 years old $=\frac{1}{5}$

Number of passengers who are 9 years old $=\frac{1}{5}$

E(X=6+X=7+X=8+X=9)

  =6 × P(6) +7 ×P(7)+8×P(8)+9×P(9)

  $=6\times \frac{1}{2}+7\times \frac{1}{10}+8\times \frac{1}{5}+9\times \frac{1}{10}\\\\ =3+0.7+1.6+0.9\\\\ =3+2.3+0.9\\\\=6.2$

Option A :6 (approx) ,appears true.

2.)

Sum of total frequency =3+7+2+3+5=20

$P(1)=\frac{3}{20}=0.15, P(2)=\frac{7}{20}=0.35,P(3)=\frac{2}{20}=0.10, P(4)=\frac{3}{20}=0.15,P(6)=\frac{5}{20}=0.25$

Option C:  X 1 2 3 4 5

P 0.15 0.35 0.10 0.15 0.25

is true.

Answer 2

Number 1 is B) 7.1 years