I need help ASAP please

9(a+2)=9 <br> con comprobación plisss!!

icang [17]

Answer:

9a+18=9

9a=-9

a=-1

Step-by-step explanation:

6 0

2 years ago

The school cafeteria surveyed students to see what their favorite lunch is, and the

Sergio039 [100]

Answer:

40%

Step-by-step explanation:

Degree representing students who prefer burgers = 144°

Percentage of students who like burger = $\frac{144}{360} \times 100$

$= 0.4 \times 100$

$= 40 percent$

Percentage of students who offered burger = 40%

3 0

2 years ago

write the equation of the line using the given information. type your awnser in slope intercept form,y=mx+b

faltersainse [42]

Answer:

y=3/-1x+4

Step-by-step explanation:

Okay so first thing you need to know is that if there is an ordered pair (x, y) where x is 0, your y-intercept is your y. For example, your problem has (0, 4) your x is 0 and your y is 4. Therefore your y-intercept is 4 which is the b. To find your mx, or slope, you need to do (y2-y1)/(x2-x1). Your y2 will be your y in your second ordered pair and your y1 will be in your y in the first ordered pair. Same for your x. So, (4-1)/(0-1) which equals 3/-1. 3/-1 is your slope. So, your answer in slop intercept form is: y= 3/-1x+4. You could also try y= -3x+4 if that makes you more comfortable.

I know this is long this is my first time doing this lol.

5 0

2 years ago

Which side lengths form a right triangle?

Stels [109]

Answer:

B) 1, 8, √65

Step-by-step explanation:

For 3 side lengths to form a triangle the sum of two random sides must be bigger than the third side and their differences must be smaller than the third side.

1+8 > √65 because √65 is approximately 8.1

8-1 < √65

4 0

2 years ago

Read 2 more answers

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

2 years ago