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3 years ago

What is a tree diagram? can you make one?

1 answer:

8 0

DescriptionIn probability theory, a tree diagram may be used to represent a probability space. Tree diagrams may represent a series of independent events or conditional probabilities. Each node on the diagram represents an event and is associated with the probability of that event. You can make one.

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Solve for x please, need help

stellarik [79]

$-3x=15\\\\ x=-5$

4 0

3 years ago

Read 2 more answers

What is the length of BC in the right triangle below

Anna [14]

Answer:

<h2>15 units</h2>

The length of BC is 15 units.

Solution,

Hypotenuse(h)=?

perpendicular(p)=12

base(b)=9

Using Pythagoras theorem,

${h}^{2} = {p}^{2} + {b}^{2} \\ or \: {h}^{2} = {12}^{2} + {9}^{2} \\ or \: {h}^{2} = 12 \times 12 + 9 \times 9 \\ or \: {h}^{2} = 144 + 81 \\ or \: {h}^{2} = 225 \\ or \: h = \sqrt{225} \\ or \: h = \sqrt{ {15}^{2} } \\ h = 15$

hope this helps...

Good luck on your assignment....

6 0

4 years ago

Read 2 more answers

Mark had 312 books. He has 11 times more fiction than nonfiction. How many fiction does he have

andrew11 [14]

He has about 28 fiction books. Since 312 divided by 11 is equal to 28.3636363636, you can't have a decimal number for the amount of books, so you round down to 28.

8 0

3 years ago

The midpoint for 3.99 and 4

vodka [1.7K]

3.995 is the midpoint

4 0

4 years ago

Nitrates are groundwater contaminants derived from fertilizer, septic tank seepage and other sewage. Nitrate poisoning is partic

o-na [289]

Answer:

a) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

b) $n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Solution to the problem

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

Part a

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Since we don't have prior information about the population proportion we can use ase estimator $\hat p =0.5$ . And replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

Part b

For thi case the estimator for p is $\hat p =0.07$

$n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

4 0

3 years ago