Psychiatrists estimate that 1 in 100 adults suffers from bipolar disorder. Use the normal approximation to the binomial distribution to estimate the probability that in a city of 10,000 people there are more than 120 people who are bipolar.

Respuesta :

Answer:

0.0222 is the probability that in a city of 10,000 people there are more than 120 people who are bipolar.

Step-by-step explanation:

We are given the following in the question:

Probability of adult suffering from bipolar disorder =

[tex]p =\dfrac{1}{100} = 0.01[/tex]

Sample size, n = 10000

We have to use normal approximation to the binomial distribution to estimate the probability.

Normal approximation:

[tex]\mu = np = 10000(0.01) = 10\\\sigma = \sqrt{np(1-p)} = \sqrt{10000(0.01)(1-0.01)} = 9.95[/tex]

The distribution of adults suffering from bipolar disorder follows a normal distribution with mean 100 and standard deviation 9.5

Formula:

[tex]z_{score} = \displaystyle\frac{x-\mu}{\sigma}[/tex]

We have to evaluate:

P(more than 120 people are bipolar)

P(x > 120)

[tex]P( x > 120) = P( z > \displaystyle\frac{120 - 100}{9.95}) = P(z > 2.010)[/tex]

[tex]= 1 - P(z \leq 2.010)[/tex]

Calculation the value from standard normal z table, we have,  

[tex]P(x > 610) = 1 - 0.9778 = 0.0222 = 2.22\%[/tex]

0.0222 is the probability that in a city of 10,000 people there are more than 120 people who are bipolar.