Decide which of the two points on the graph of the line X=0 A. 0,7 B. -4,0

You estimated the average rental cost of a 2 bedroom apartment in Denton. A random sample of 16 apartments was taken. The sample

Zigmanuir [339]

Answer:

The new sample size required in order to have the same confidence 95% and reduce the margin of erro to $60 is:

n=28

Step-by-step explanation:

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".

Assuming the X follows a normal distribution

$X \sim N(\mu, \sigma=160)$

And the distribution for $\bar X$ is:

$\bar X \sim N(\mu, \frac{160}{\sqrt{n}})$

We know that the margin of error for a confidence interval is given by:

$Me=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

The next step would be find the value of $\z_{\alpha/2}$ , $\alpha=1-0.95=0.05$ and $\alpha/2=0.025$

Using the normal standard table, excel or a calculator we see that:

$z_{\alpha/2}=\pm 1.96$

If we solve for n from formula (1) we got:

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

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

And we have everything to replace into the formula:

$n=(\frac{1.96(160)}{78.4})^2 =16$

And this value agrees with the sample size given.

For the case of the problem we ar einterested on Me= $60, and we need to find the new sample size required to mantain the confidence level at 95%. We know that n is given by this formula:

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

And now we can replace the new value of Me and see what we got, like this:

$n=(\frac{1.96*160}{60})^2 =27.32$

And if we round up the answer we see that the value of n to ensure the margin of error required $Me=\pm 60$ $ is n=28.

5 0

3 years ago

0.8 is 10 times as great as what decimal

Aleks04 [339]

0.08.
0.8/10 is 0.08
the answer is 0.08

3 0

3 years ago

a. For what values of x does f (x )equals 3 x plus 3 sine x have a horizontal tangent line? b. For what values of x does f (x )

laila [671]

Answer:

(a)Therefore the value of x= $\pi$

(b) Therefore the value of x $=\frac{\pi}{2}$

Step-by-step explanation:

Horizontal tangent line: The first order derivative of a function gives the slope of the tangent of the function. The slope of horizontal line is zero.If the slope of tangent line is zero then the tangent line is called horizontal tangent line.

(a)

Given function is,

$f(x)= 3x+3sin x$

Differential with respect to x

$f'(x)=3+3cos x$

For horizontal tangent line, f'(x)=0

3+ 3 cos x= 0

⇒3 cos x=-3

⇒cos x=-1

⇒x = 180° $=\pi$

Therefore the value of x= $\pi$

(b)

Given that, the slope is 3.

Then,f'(x)=3

3+ 3 cos x= 3

⇒3 cos x= 3-3

⇒cos x=0

⇒x = 90° $=\frac{\pi}{2}$

Therefore the value of x $=\frac{\pi}{2}$

5 0

3 years ago

5- One month Selena made 4 withdrawals for $ 20and 2 withdrawals for $ 80 from her account .Howdid the withdrawals change the am

notsponge [240]

Answer: total withdrawal: 80+ 160= 240

Step-by-step explanation:

She withdrawl from her bank acount for 4 times for 20 dollars means that you multiply 20 with 4= 80 and she also made two withdrawal for 80 so you take 80 mutiply by 2= 160 plus all together is the total amount of withdrawal that she took from the bank

6 0

3 years ago

Please help me I will really appreciate it!!!

slega [8]

Answer:

$\displaystyle r=\sqrt[3]{\frac{3V}{4\pi}}$