contestada

A telephone survey uses a random digit dialing machine to call subjects. the random digit dialing machine is expected to reach a live person 15% of the time. in eight attempts, what is the probability of achieving exactly two successful calls?

Respuesta :

merlynthewhizz
P([tex]r[/tex] successes in [tex]n[/tex] trials) = ⁿ[tex] C_{r} [/tex]×[tex] [P(Success)^{r}] [/tex]×[tex] [P(failure)]^{n-r} [/tex]

We have
[tex]n=8[/tex]
[tex]r=2[/tex]
[tex]P(Success)=0.15[/tex]
[tex]P(Failure)=0.85[/tex]

Substitute these values into the formula, we have
P( 2 success in 8 trials) = ⁸C₂ × (0.15)² × (0.85)⁶
P( 2 success in 8 trials) = 0.2376.... ≈ 0.24 = 24%

Otras preguntas