Help me with this one

The distance of AB = [?]<br> Round to the nearest tenth.<br> No links and actual help plz!

FrozenT [24]

AB = 5.6
hope this is helpful!

8 0

3 years ago

GRE Test: The Graduate Record Examination (GRE) is a test required for admission to many US graduate schools. Student’s scores o

Zepler [3.9K]

Answer:

a) $\bar X=144.3$

b) The 95% confidence interval would be given by (138.846;149.754)

c) n=34

d) n=298

e) n=1190

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".

We can calculate the sample mean with this formula:

$\bar X = \frac{\sum_{i=1}^n x_i}{n}$

$\bar X=144.3$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=8.8$ represent the population standard deviation

n=10 represent the sample size

a) Find a point estimate of the population mean

We can calculate the sample mean with this formula:

$\bar X = \frac{\sum_{i=1}^n x_i}{n}$

$\bar X=144.3$

b) Construct a 95% confidence interval for the true mean score for this population.

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $t_{\alpha/2}=1.96$

Now we have everything in order to replace into formula (1):

$144.3-1.96\frac{8.8}{\sqrt{10}}=138.846$

$144.3+1.96\frac{8.8}{\sqrt{10}}=149.754$

So on this case the 95% confidence interval would be given by (138.846;149.754)

Part c

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =+20 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025;0;1)", and we got $z_{\alpha/2}=1.960$ , replacing into formula (5) we got:

$n=(\frac{1.960(8.8)}{3})^2 =33.05 \approx 34$

So the answer for this case would be n=34 rounded up to the nearest integer

Part d

$n=(\frac{1.960(8.8)}{1})^2 =297.493 \approx 298$

So the answer for this case would be n=298 rounded up to the nearest integer

Part e

$n=(\frac{1.960(8.8)}{0.5})^2 =1189.97 \approx 1190$

So the answer for this case would be n=1190 rounded up to the nearest integer

7 0

3 years ago

Tanisha's website had x visitors on Friday. On Saturday, it had 500 more visitors than it did on Friday. The total

liq [111]

If the number of visitors on Friday, Saturday, and Sunday is x, x + 500, and x + 250. Then the total number of visitors will be 3x + 750.

<h3>What is Algebra?</h3>

Algebra is the study of mathematical symbols, and the rule is the manipulation of those symbols.

Tanisha's website had x visitors on Friday.

On Saturday, it had 500 more visitors than it did on Friday. That is x + 500

The total number of visitors on Friday and Saturday was twice the number on Sunday. That is (2x + 500)/2

Then the total number of the visitors will be

→ Friday + Saturday + Sunday

Then we have

$\rm \rightarrow x + x + 500 + \dfrac{2x + 500}{2}\\\\\rightarrow 2x + 500 + x + 250\\\\\rightarrow 3x + 750$

More about the Algebra link is given below.

brainly.com/question/953809

#SPJ1

6 0

2 years ago

At what points does the helix r = left angle bracketsin(t), cos(t), tright angle bracket intersect the sphere x 2 + y 2 + z 2 =

r-ruslan [8.4K]

Answer:

the points are = (0.1045, 0.9945, 6) and ( -0.1045, 0.9945, -6)

Step-by-step explanation:

The detailed steps and appropriate substitution is as shown in the attached file.

4 0

3 years ago

andreas car gets 25miles per gallon of gas. her vacation cabin is 190 miles away. how many gallons of gas will she need to get t

aliina [53]

You'll need 7.6 gallons of gas... all you do is divide 190 by 25 and get 7.6 as your answer

3 0

3 years ago

Help me with this one​

Help me with this one