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2 years ago

12

I really need this ASAP. There are 25 students in a class. How many ways can the teacher (randomly) pick two students for the le

ad roles in the class play?

1 answer:

kicyunya [14]2 years ago

4 0

Answer:

The teacher can do many different ways, I dont think there is a limited answer.

Step-by-step explanation:

If there is can you plz give me the options so I know what type of math you are doing

You might be interested in

HELP ME PLEASE REALLY IMPORTANT OR ILL GET IN TROUBLE!! WILL MARK AS BRAINLEST IF YOU GET IT CORRECT!!

dmitriy555 [2]

Answer:

2n + 11

Step-by-step explanation:

You can combine 4n and -2n.

You get 2n + 11

8 0

2 years ago

Please help me on these questions and explain it thanks

BlackZzzverrR [31]

For problem 2:

The answer would be B) Car A travels more miles per gallon of fuel than Car B.

This is because Car B is shown on the graph to travel the same number of miles as Car A using 16 gallons of fuel, while Car A uses only 4 gallons. Thus, Car A travels further with less fuel.

For problem 3:

Let's write out the equation and try to solve.
5x + 1 = 3x + 7

First, subtract 3x from both sides.
5x - 3x + 1 = 3x - 3x + 7
2x + 1 = 7
Now, subtract one from both sides.

2x + 1 - 1 = 7 - 1
2x = 6

Finally, divide both sides by 2.
2x/2 = 6/2

x = 3

You should only get B) One solution

Hope that helped!

8 0

3 years ago

Pointed teeth help tear apart food, and large, flat teeth are used to grind food. Based on this information, what types of teeth

ira [324]

Answer:

the meat eating animals need the pointed teeth and the flat teeth. the animals that eat plants only need the flat teeth

3 0

3 years ago

In 2002, the mean age of an inmate on death row was 40.7 years with a standard deviation of 9.6 years according to the U.S. Depa

marissa [1.9K]

Answer:

The <em>95% confidence interval</em> for the current mean age of death-row inmates is between 42.23 years and 35.57 years.

Step-by-step explanation:

The <em>confidence interval</em> of the mean is given by the next formula:

$\\ \overline{x} \pm z_{1-\frac{\alpha}{2}}\frac{\sigma}{\sqrt{n}}$ [1]

We already know (according to the U.S. Department of Justice):

The (population) standard deviation for this case (mean age of an inmate on death row) has a standard deviation of 9.6 years ( $\\ \sigma = 9.6$ years).
The number of observations for the sample taken is $\\ n = 32$ .
The sample mean, $\\ \overline{x} = 38.9$ years.

For $\\ z_{1-\frac{\alpha}{2}}$ , we have that $\\ \alpha = 0.05$ . That is, the <em>level of significance</em> $\\ \alpha$ is 1 - 0.95 = 0.05. In this case, then, we have that the <em>z-score</em> corresponding to this case is:

$\\ z_{1-\frac{\alpha}{2}} = z_{1-\frac{0.05}{2}} = z_{1-0.025} = z_{0.975}$

Consulting a cumulative <em>standard normal table</em>, available on the Internet or in Statistics books, to find the z-score associated to the probability of, $\\ P(z$ , we have that $\\ z = 1.96$ .

Notice that we supposed that the sample is from a population that follows a <em>normal distribution</em>. However, we also have a value for n > 30, and we already know that for this result the sampling distribution for the sample means follows, approximately, a normal distribution with mean, $\\ \mu$ , and standard deviation, $\\ \sigma_{\overline{x}} = \frac{\sigma}{\sqrt{n}}$ .

Having all this information, we can proceed to answer the question.

Constructing the 95% confidence interval for the current mean age of death-row inmates

To construct the 95% confidence interval, we already know that this interval is given by [1]:

$\\ \overline{x} \pm z_{1-\frac{\alpha}{2}}\frac{\sigma}{\sqrt{n}}$

That is, we have:

$\\ \overline{x} = 38.9$ years.

$\\ z_{1-\frac{\alpha}{2}} = 1.96$

$\\ \sigma = 9.6$ years.

$\\ n = 32$

Then

$\\ 38.9 \pm 1.96*\frac{9.6}{\sqrt{32}}$

$\\ 38.9 \pm 1.96*\frac{9.6}{5.656854}$

$\\ 38.9 \pm 1.96*1.697056$

$\\ 38.9 \pm 3.326229$

Therefore, the Upper and Lower limits of the interval are:

Upper limit:

$\\ 38.9 + 3.326229$

$\\ 42.226229 \approx 42.23$ years.

Lower limit:

$\\ 38.9 - 3.326229$

$\\ 35.573771 \approx 35.57$ years.

In sum, the 95% confidence interval for the current mean age of death-row inmates is between 42.23 years and 35.57 years.

Notice that the "mean age of an inmate on death row was 40.7 years in 2002", and this value is between the limits of the 95% confidence interval obtained. So, according to the random sample under study, it seems that this mean age has not changed.

7 0

3 years ago

The question is in the picture please explain.

lapo4ka [179]

Answer:

x = 78

Step-by-step explanation:

Look at Triangle DBH. Two of its angles are known. Let y = <DHB

47 + 31 + y = 180 All triangles have 180 degrees. Combine the left.

78 + y = 180 Subtract 78 from both sides.

78-78+y = 180-78 Combine

y = 102

Notice that y + x = 180 They form a straight line.

102 + x = 180 Subtract 102 from both sides.

x = 78

You should notice that x is an exterior angle. (I didn't at first).

Exterior angles are the sum of the two remote interior angles which in this case, are 31 + 47 = 78

Much shorter and much easier.

3 0

3 years ago