Mr.N just bought a new car, and her asks 3 of his students to try to guess the color. Here's what they thought:

The U.S. Census Bureau conducts a study to determine the time needed to complete the short form. The Bureau surveys 200 people.

NISA [10]

Answer:

$8.2-2.58\frac{2.2}{\sqrt{18}}=6.86$

$8.2+2.58\frac{2.2}{\sqrt{18}}=9.54$

So on this case the 90% confidence interval would be given by (6.86;9.54) And the error is given by:

$ME= 2.58\frac{2.2}{\sqrt{18}} =1.338$

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".

$\bar X=8.2$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=2.2$ represent the population standard deviation

n represent the sample size

Solution to the problem

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 0.90 or 90%, the value of $\alpha=0.1$ 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):

$8.2-2.58\frac{2.2}{\sqrt{18}}=6.86$

$8.2+2.58\frac{2.2}{\sqrt{18}}=9.54$

So on this case the 90% confidence interval would be given by (6.86;9.54) And the error is given by:

$ME= 2.58\frac{2.2}{\sqrt{18}} =1.338$

8 0

2 years ago

Read 2 more answers

Help me please ASAP!!!!

gogolik [260]

It took 8 weeks because follow 15 to the dot then go down and you see the answer

3 0

3 years ago

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Can someone help me with this problem?

dlinn [17]

Answer

7 or 4

because do you see how v is lined 2 I don't remember if you times or divide .I'm going to go with times.

So what is 2 x 10 since V=10

2 x 10=20

Then we are going to divide so what is 20 divided by 5 since e=5

20 divided by 5=4

Next our last step what is 4 + 3=7 and there's are answer.

The answer is divide then this would be the answer.

so V(10) divided by 2=5 divided by e(5) =1 + 3=4

Hope this helps have a great day

8 0

2 years ago

Interest: $160.67<br> Principal: $2000<br> Rate:<br> %<br> Time: 8 months

ivanzaharov [21]

Answer:

12.05%

Step-by-step explanation:

First, converting R percent to r a decimal

r = R/100 = 12.050249999994%/100 = 0.12050249999994 per year,

then, solving our equation

I = 2000 × 0.12050249999994 × 0.666666666667 = 160.67

I = $ 160.67

The simple interest accumulated

on a principal of $ 2,000.00

at a rate of 12.050249999994% per year

for 0.666666666667 years is $ 160.67.

4 0

2 years ago

What type of number is 0.2782

givi [52]

It is a decimal answer if you used a calculater, and divided then got that answer, then try the same problems just switch the order that you put in the calculater, ex: if you divide 408÷1201 ,and then you get an answer like that, then you would divide it like 1201÷408
I hope this helped :)

4 0

3 years ago

Read 2 more answers