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3 years ago

REwaRDiNG BRAINLY TO CORRECT

Mathematics

2 answers:

vfiekz [6]3 years ago

6 0

Answer:

54 millimeters

Step-by-step explanation:

The median length would be in the middle of the values in order, so you could order the numbers 50,50,52,53,54,55,55,55,57. You would then find the middle value which would be the 5th value in a list of 9. In this case, it would be 54 millimeters.

il63 [147K]3 years ago

6 0

Answer:

Step-by-step explanation:

Put the numbers in order: 50,50,52,53,54,55,55,55,57 and the middle one is your median in this case 54 is in the middle so ye

Good luck!

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Lena [83]

Answer:

cool, how long did it take

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3 years ago

Read 2 more answers

you work at a hair salon and get left a 35 tip on a 112 haircut and color service . What percent tip did your customer give you

levacccp [35]

31.25 percent of 112 is 35

7 0

3 years ago

B) A monthly service fee to download e-books is $4.95, plus $3.99 per book downloaded. Write an

pickupchik [31]

Answer:

$4.95 + $3.99b = c

I can't make a graph but start at 4.95 on the graph and move up 3.99 every time you go to the right once

7 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 95% confidence interval for the current mean age of death-row inmates is between 42.23 years and 35.57 years.

Step-by-step explanation:

The confidence interval 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 level of significance $\\ \alpha$ is 1 - 0.95 = 0.05. In this case, then, we have that the z-score 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 standard normal table, 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 normal distribution. 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

A cup of coffee at 95 degrees Celsius is placed in a room at 25 degrees Celsius. Suppose that the coffee cools at a rate of 2 de

Roman55 [17]

Answer:

See Explanation

Step-by-step explanation:

For an object at temperature T and supposing that the ambient temperature is Ta then we can write the differential equation that typifies the Newton law of cooling as follows;

dT/dt=-k(T-Tₐ)

dT/dt = 2 degrees Celsius per minute

T = 70 degrees Celsius

Ta = 25 degrees Celsius

2 = -k(70 - 25)

-k = 2/(70 - 25)

k = - 0.044

Hence we can write;

dT/dt=-(- 0.044)(95-25)

dT/dt= 3 degrees Celsius per minute

4 0

3 years ago