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A binomial event has n = 30 trials. The probability of success for each trial is 0.30. Let x be the number of successes of the event during the 30 trials. What are μx and σx?
μx = 2.51 and σx = 9
μx = 21 and σx = 6.3
μx = 9 and σx = 2.51
μx = 6.3 and σx = 21

Respuesta :

Answer:

Correct: Third option μx = 9 and σx = 2.51

Step-by-step explanation:

Binomial Distribution

Being p the probability of success of an individual event, q the probability of failure (q=1-p) and n the number of independent trials of that event, the expected value or mean of the distribution is

[tex]\mu_x=np[/tex]

And the variance is

[tex]\sigma_x ^2=npq[/tex]

The standard deviation is

[tex]\sigma_x=\sqrt{npq}[/tex]

The given binomial distribution has the following parameters

n = 30, p = 0.3, q = 1 - 0.3 = 0.7. The mean is

[tex]\mu_x=(30)(0.3)=9[/tex]

The standard deviation is

[tex]\sigma_x=\sqrt{(30)(0.3)(0.7)}=\sqrt{6.3}[/tex]

[tex]\sigma_x=2.51[/tex]

The third option is the correct one