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3 years ago

The average of two numbers is twice the positive difference between if the smaller number is 9 what's my answer?

1 answer:

7 0

Let b, be the smallest number :Note the average of a+b = (a+b)/2
(a+b)/2 = 2(a-b)
a+b = 4(a-b)
a+b = 4a - 4b, but b = 9, then plug:
a+9 = 4a - 36
-3a = -45
3a = 45
and a = 15

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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

Need help with this math question, keep getting the first part correct but the other 2 parts of the function are incorrect. Not

Akimi4 [234]

Step-by-step explanation:

Here are four steps to help solve any math problems easily:

Read carefully, understand, and identify the type of problem. ...

Draw and review your problem. ...

Develop the plan to solve it. ...

Solve the problem.

4 0

2 years ago

The LSN basketball team had 292 fans at a game. Adults paid $3.00 to get in and students paid $2.00. A total of $756.00 was coll

rjkz [21]

Answer:

x (378) + y (378) =

Step-by-step explanation:

First i split 756.00 in half so basically what ever is multiplied by two to get 756 and i got 378. So since x = 3.00 and y = 2.00, it would come out to this:

3.00 x 378 = x (378) =

2.00 x 378 = y (378) =

So:

x (378) + y (378) =

im sorry if i got it wrong-

5 0

3 years ago

What is the volume of the following rectangular prism?

Marianna [84]

Answer:

The volume is 7.9 units

Step-by-step explanation:

4 0

4 years ago

Read 2 more answers

Write three numbers greater 20 that have a 9 as a factor

Murrr4er [49]

27, 36, and 45.
Here's a good nines trick.
9
18
27
36
45
If you pay attention is just adds a ten and minuses a 1 from each number.
8,7,6,5. And 1,2,3,4.
Hope this helps :)

8 0

4 years ago

Read 2 more answers