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MariettaO [177]

3 years ago

6

A bag contains 5 red marbles and 4 green marbles. What is the probability of choosing a red marble then a green marble, without

replacement?

1 answer:

STALIN [3.7K]3 years ago

5 0

It will be 5 out of 9 times you will pull a red marble

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A report indicated that 37% of adults had received a bogus email intended to steal personal information. Suppose a random sample

fiasKO [112]

Answer:

5.05% probability that no more than 34% had received such an email.

Step-by-step explanation:

We use the binomial approximation to the normal to solve this problem.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$n = 700, p = 0.37$

$\mu = E(X) = np = 700*0.37 = 259$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{700*0.37*0.63} = 12.77$

In a random sample of 700 adults, what is the probability that no more than 34% had received such an email?

34% is 0.34*700 = 238

So this probability is the pvalue of Z when X = 238.

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{238 - 259}{12.77}$

$Z = -1.64$

$Z = -1.64$ has a pvalue of 0.0505

5.05% probability that no more than 34% had received such an email.

7 0

3 years ago

Solve y = x + 4 for x,<br> Ox=y - 4<br> Ox=y+ 4<br> Ox=-y + 4<br> Ox=-y - 4

Hitman42 [59]

Answer:

x=y+4

Step-by-step explanation:

bc you add four bc it's the opposite

5 0

3 years ago

A window is being replaced with tinted glass. The plan at the right shows the design of the window. Each unit length represents

PolarNik [594]

The answer is $911.68.

After a little research on the internet, I found the design of the window.
First, you need to find the area of the window which is a composite figure made up of a rectangle and a circle. So, the total area (A) is the sum of the area of the rectangle (A1) and the area of the circle (A2).

Area of the rectangle with length l and width w is:
A = l * w
According to the image, l = 5 ft and w = 4 ft.
A1 = 5 * 4 = 20 ft²

Area of the circle with radius r is:
A = r²π
According to the image, r = 2 ft.
A2 = 2² * 3.14 = 12.56 ft²

The area of the window is:
A = A1 + A = 20 ft² + 12.56 ft² = 32.56 ft²

<span>The glass costs $28 per square foot, so to replace the glass will cost:
</span>32.56 ft² * $28/ft² = $911.68

7 0

4 years ago

What is the width (or height) of the parking lot?

Gre4nikov [31]

The width is 146.0315533981 cuz 12033÷82.4 is 146.0315533981

6 0

3 years ago

1. Label axes according to input/output.

Rudiy27

Answer:height (in), arm span (in), (30,27)

Step-by-step explanation:

3 0

3 years ago