Match the symbol with its corresponding category.

What are the coordinates of point B?

zaharov [31]

Point a is at (-2,4) => (x1,y1)

Midpoint is (2.5, 3.5) => (a,b)

Point B is (x2, y2)

To find midpoint we use formula

$(a=\frac{x_1+x_2}{2} , b= \frac{y_1+y_2}{2})$

a= 2.5, b= 3.5, x1= -2 and y1= 4

Plug in all the values and findout x2, y2

$(2.5=\frac{-2+x_2}{2} , 3.5= \frac{4+y_2}{2})$

multiply 2 on both sides to remove fraction

(5 = -2+x2 , 7 = 4+ y2)

5 = -2+x2, so x2= 7

7 = 4+ y2, so y2= 3

The point B is ( 7, 3)

3 0

3 years ago

In a random sample of 80 teenagers, the average number of texts handled in a day is 50. The 96% confidence interval for the mean

Nastasia [14]

Answer:

a) $\bar X =\frac{46+54}{2}=50$

And the margin of error is given by:

$ME= \frac{54-46}{2}= 4$

The confidence level is 0.96 and the significance level is $\alpha=1-0.96=0.04$ and the value of $\alpha/2 =0.02$ and the margin of error is given by:

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

We can calculate the critical value and we got:

$z_{\alpha/2} = 2.05$

And if we solve for the deviation like this:

$\sigma = ME * \frac{\sqrt{n}}{z_{\alpha/2}}$

And replacing we got:

$\sigma =4 *\frac{\sqrt{80}}{2.05} =17.45$

b) $ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}=2.05 *\frac{17.45}{\sqrt{160}}=2.828$

And as we can see that the margin of error would be lower than the original value of 4, the margin of error would be reduced by a factor $\sqrt{2}$

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".

$\bar X$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma$ represent the population standard deviation

n=80 represent the sample size

Solution to the problem

Part a

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

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

For this case we can calculate the mean like this:

$\bar X =\frac{46+54}{2}=50$

And the margin of error is given by:

$ME= \frac{54-46}{2}= 4$

The confidence level is 0.96 and the significance level is $\alpha=1-0.96=0.04$ and the value of $\alpha/2 =0.02$ and the margin of error is given by:

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

We can calculate the critical value and we got:

$z_{\alpha/2} = 2.05$

And if we solve for the deviation like this:

$\sigma = ME * \frac{\sqrt{n}}{z_{\alpha/2}}$

And replacing we got:

$\sigma =4 *\frac{\sqrt{80}}{2.05} =17.45$

Part b

For this case is the sample size is doubled the margin of error would be:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}=2.05 *\frac{17.45}{\sqrt{160}}=2.828$

And as we can see that the margin of error would be lower than the original value of 4, the margin of error would be reduced by a factor $\sqrt{2}$

5 0

2 years ago

Gianna is taking a multiple choice test with a total of 100 points available. Each question is worth exactly 5 points. What woul

tatiyna

Answer:

Her test score would be an 85 because 5x3=15 and then you would subtract 15 from 100 which would be 85

equation would be x=100-(5y)

8 0

2 years ago

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Consider the following geometric series. [infinity] (−7)n − 1 8n n = 1. Find the common ratio. Determine whether the geometric s

Hatshy [7]

Answer:

d67d6d 34r2

Step-by-step explanation:

d53eududc6ttd5cf

3 0

3 years ago

What should the following rate be divided by to convert it to a unit rate?<br> 6 inches<br> 12 hours

nataly862011 [7]

Answer:

so if all of the awnsers are whole numbers it is going to be 12/12

Step-by-step explanation:

6 0

2 years ago

Read 2 more answers