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marishachu [46]

3 years ago

5

In a certain country, the true probability of a baby being a girl is 0.469. Among the next seven randomly selected births in th

e country, what is the probability that at least one of them is a boy?

1 answer:

-BARSIC- [3]3 years ago

8 0

Answer:

The probability is 0.995 ( approx ).

Step-by-step explanation:

Let X represents the event of baby girl,

The probability of a baby being a girl is, p = 0.469,

So, the probability of a baby who is not a girl is, q = 1 - 0.469 = 0.531,

Also, the total number of experiment, n = 7

Thus, by the binomial distribution formula,

$P(x)=^nC_x(p)^x q^{n-x}$

Where, $^nC_x=\frac{n!}{x!(n-x)!}$

The probability that all babies are girl or there is no baby boy,

$P(X=7)=^7C_7(0.469)^7(0.531)^{7-7}$

$=0.00499125661758$

Hence, the probability that at least one of them is a boy = 1 - P(X=7)

= 1 - 0.00499125661758

= 0.995008743382

≈ 0.995

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Read 2 more answers

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(c) $P(X > 980) = 0.00001\\\\$

Step-by-step explanation:

The given problem can be solved using binomial distribution since the product either fails or passes, the probability of failure or success is fixed and there are n repeated trials.

probability of failure = q = 0.05

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(a) What is the expected number of non-defective units?

The expected number of non-defective units is given by

$E(X) = n \times p \\\\E(X) = 1000 \times 0.95 \\\\E(X) = 950$

(b) what is the COV of the number of non-defective units?

The coefficient of variance is given by

$COV = \frac{\sigma}{E(X)}$

Where the standard deviation is given by

$\sigma = \sqrt{n \times p\times q} \\\\\sigma = \sqrt{1000 \times 0.95\times 0.05} \\\\\sigma = 6.892$

So the coefficient of variance is

$COV = \frac{6.892}{950}$

$COV = 0.007255$

(c) What is the probability of having more than 980 non-defective units?

We can use the Normal distribution as an approximation to the Binomial distribution since n is quite large and so is p.

$P(X > 980) = 1 - P(X < 980)\\\\P(X > 980) = 1 - P(Z < \frac{x - \mu}{\sigma} )\\\\$

We need to consider the continuity correction factor whenever we use continuous probability distribution (Normal distribution) to approximate discrete probability distribution (Binomial distribution).

$P(X > 980) = 1 - P(Z < \frac{979.5 - 950}{6.892} )\\\\P(X > 980) = 1 - P(Z < \frac{29.5}{6.892} )\\\\P(X > 980) = 1 - P(Z < 4.28)\\\\$

The z-score corresponding to 4.28 is 0.99999

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So it means that it is very unlikely that there will be more than 980 non-defective units.

8 0

3 years ago

9. Water is added to two containers for 16 minutes. The equations below model the ounces of

Vladimir [108]

The two containers hold 328 ounces at the they hold same amount of water.

<u>Step-by-step explanation:</u>

The equations below model the ounces of water, y, in each container after x minutes.

$y = 16x + 104$

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At the time after the start when the containers hold the same amount of water, the two equations must be equal.

⇒ $16 x + 104 = -2x^{2} + 40 x + 160$

The first step is to divide everything by 2 to make it simplified.

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Now put everything on the left .

$x^2 + 8 x - 20 x + 52 - 80 = 0$

Add the like terms together to further reduce the equation

$x^2 - 12 x - 28 = 0$

Factorizing the equation to find the roots of the equation.

Here, b = -12 and c = -28

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c is the product of the roots ⇒ -14 × 2 = -28

Therefore, (x-14) (x+2) = 0
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5 0

3 years ago