Daily Brainliest #1 - Needs to be correct / First correct person to answer simple explanation gets today's brainliest

Hazel bought a bread toaster from an online company the original price of the Bread toaster Was $50 she received a 20% discount

alexgriva [62]

C. 20% minus 10% is 10%.

3 0

3 years ago

My brother wants to estimate the proportion of Canadians who own their house.What sample size should be obtained if he wants the

AVprozaik [17]

Answer:

a) $n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

b) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

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".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

If solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Part a

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.64$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

Part b

For this case since we don't have a prior estimate we can use $\hat p =0.5$

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

8 0

3 years ago

Please help!!! I’m so confused on how to solve this!

-Dominant- [34]

Let's first write the equation given

x²+6x-13=0

They have told us to use "Completing the square" method.

So we need write x²+6x-13 as a whole square.

x²+6x-13=0

x²+(2*3*x)-9-4 = 0

x²+(2*3*x)-3²=4

Now we can write the LHS as:

(x - 3)²=2²

Hence,

x-3 can either be 2 or -2

Now,

x - 3=2

x=5

Or,

x - 3=-2

x=1

Therefore now we know that x can either be 1 or 5. So the correct answer is Option B.

8 0

4 years ago

Read 2 more answers

Which expression is equivalent to √48x5, if x> 0?

Lerok [7]

Answer:

C. 4x²√(3x)

Step-by-step explanation:

if x > 0

$\sqrt{48x^{5}} =\sqrt{48} \times \sqrt{x^{5}}$

$=\sqrt{16\times 3} \times \sqrt{x^{4}\times x}$

$=\sqrt{16} \times \sqrt{3} \times \sqrt{x^{4}} \times \sqrt{x}$

$=4\times \sqrt{3} \times \sqrt{\left( x^{2}\right)^{2} } \times \sqrt{x}$

$=4\times \sqrt{3} \times x^{2}\times \sqrt{x}$

$=4\times x^{2} \times \sqrt{3} \times \sqrt{x}$

$=4\times x^{2}\times \sqrt{3x}$

8 0

2 years ago

Please help me i dont know what the answer is ??

Assoli18 [71]

To answer this, we need to use the rules of geometric shapes. An equilateral triangle is equiangular, meaning all its angle measures are equal. Since all triangles' angles add up to 180°, simply divide 180 by three to find the angle measure of each angle:
$\frac{180}{3} = 60$
Therefore, the measure of the triangle's angle is 60°

Next, we know that a characteristic of a rectangle is that each angle must be a right angle, or an angle with a measure of 90°.

Now, all we have to do is use the sum of all the angle measures to figure out the missing piece:
$90=x+60+12 \\ 90=x+72 \\ 90-72=(x+72)-72 \\ 18=x$

The missing angle measure, angle x, equals 18°.

Hope this helps!

7 0

3 years ago