CAN SOMEONE HELP ME PLEASE ASAP!

Two variables are said to be negatively associated if

Vaselesa [24]

Answer: large values of one variable are associated with small values of the other

Step-by-step explanation:

5 0

2 years ago

An SRS of 350 high school seniors gained an average of x¯=21 points in their second attempt at the SAT Mathematics exam. Assume

Lynna [10]

Answer:

a) $21-2.58\frac{52}{\sqrt{350}}=13.83$

$21+2.58\frac{52}{\sqrt{350}}=28.17$

So on this case the 99% confidence interval would be given by (13.83;28.17)

b) $ME=2.58\frac{52}{\sqrt{350}}=7.17$

c) $ME=2.58\frac{52}{\sqrt{100}}=13.42$

d) D. Decreasing the sample size increases the margin of error, provided the confidence level and population standard deviation remain the same.

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".

Part a

$\bar X=21$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=52$ represent the population standard deviation

n=350 represent the sample size

99% confidence interval

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 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

Now we have everything in order to replace into formula (1):

$21-2.58\frac{52}{\sqrt{350}}=13.83$

$21+2.58\frac{52}{\sqrt{350}}=28.17$

So on this case the 99% confidence interval would be given by (13.83;28.17)

Part b

The margin of error is given by:

$ME=2.58\frac{52}{\sqrt{350}}=7.17$

Part c

The margin of error is given by:

$ME=2.58\frac{52}{\sqrt{100}}=13.42$

Part d

As we can see when we reduce the sample size we increase the margin of error so the best option for this case is:

D. Decreasing the sample size increases the margin of error, provided the confidence level and population standard deviation remain the same.

6 0

2 years ago

What fraction is greater than 2/3

lutik1710 [3]

2/3 is basically 0.6666666667 which is the same as 66% so any percentage bigger than 66% such as 75% (0.75) which is 3/4 (as a fraction) is bigger than 2/3

8 0

2 years ago

Please take a look at the imageeeeeeeeeeeee

kramer

Answer:

I'm not alone

It's just me and your ghost

And this cripplin' depression

I thought I learned my lesson

But I threw out my phone

And I burned all your clothes

And now I'm not alone

It's just me and your ghost

[Verse 1]

I got four red bottoms up in flames at my place now (Place now)

I burned three Chanel dresses, three words we don't say now (Say now)

And it's hard not to drink when it's the one thing I think about

It's a lot of spiders in the attic, I don't mean to be dramatic

But I think it's kinda tragic who we magically became now

[Chorus]

I'm not alone

It's just me and your ghost

And this cripplin' depression

I thought I learned my lesson

But I threw out my phone

And I burned all your clothes

And now I'm not alone

It's just me and your ghost

[Post-Chorus]

Me and your ghost

Me and your ghost (Yeah)

[Verse 2]

Tell me what I'm s'posed to do with all these pictures on my iPhone

Even all them videos only you and I know

You never cared about me, you just care about the likes though

Every time you pop up, you should see my stupid eye roll

I can't even kick it with the homies that we both know

I can't even vist with any places that we used to go

Now all I got is just the memories of us though

Burn it all down to the ground with your ghost

[Chorus]

I'm not alone

It's just me and your ghost

And this cripplin' depression

I thought I learned my lesson

But I threw out my phone

And I burned all your clothes

And now I'm not alone

It's just me and your ghost

[Post-Chorus]

Me and your ghost

[Bridge]

I wish I could take back summer nights

Erase all the vibes

Leave the memories out to dry

Delete forever, no archive

Take the words you said to me

Hold on to them intentionally

I know that eventually

I'ma set fire to the one thing I love the most

Burn it all to the ground with your ghost

[Chorus]

I'm not alone

It's just me and your ghost

And this cripplin' depression

I thought I learned my lesson

But I threw out my phone

And I burned all your clothes

And now I'm not alone

It's just me and your ghost

[Post-Chorus]

Me and your ghost

Step-by-step explanation:

3 0

3 years ago

how many gallons of a 50 antifreeze solution must be mixed with 90 gallons of 20% antifreeze to get a mixture that is 40% antifr

Tamiku [17]

Try this:
1) note that weight of pure antifreeze before mixing and after mixing is the same. So, if 'x' is weight of pure antifreeze in 50% solution, it is possible to make up equation before mixing: 0.5x+0.2*90.
2) there are 0.2*90=18 gal. of pure antifreeze in the 20% solution. If 'x' gal. is the weight of pure antifreeze in 50% sol. and 18 gal. is the weight of pure antifreeze in 20% sol., it is possible to make up an equation after mixing: 0.4(x+18).
3) using the both parts: 0.5x+0.2*90=0.4(x+18) ⇒ x=54 gal. of <u>pure</u> weight.
4) to find 50% solution of 54 gal. pure weight just 54:0.5=108 gal.
Answer: 108 gal.

3 0

3 years ago