Some one please help

A survey shows that college students spend on average about $20 per month on Yum Good Ramen. a. Assume that the survey was condu

lawyer [7]

Answer:

a) The 95% confidence interval would be given by (19.168;20.832)

b) The 95% confidence interval would be given by (19.182;20.416)

c) The 95% confidence interval would be given by (19.412;20.588)

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".

$\bar X$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma$ represent the population standard deviation

n represent the sample size

Part a

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 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

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

$20-1.96\frac{6}{\sqrt{200}}=19.168$

$20+1.96\frac{6}{\sqrt{200}}=20.832$

So on this case the 95% confidence interval would be given by (19.168;20.832)

Part b

For this case we just need to change the value for the deviation

$20-1.96\frac{3}{\sqrt{200}}=19.584$

$20+1.96\frac{3}{\sqrt{200}}=20.416$

So on this case the 95% confidence interval would be given by (19.182;20.416)

Part c

For this case we change again the deviation and the sample size.

$20-1.96\frac{6}{\sqrt{400}}=19.412$

$20+1.96\frac{6}{\sqrt{400}}=20.588$

So on this case the 95% confidence interval would be given by (19.412;20.588)

7 0

3 years ago

Factor:

hammer [34]

The answer is 2(b^2-bc+c^2-ac+a^2-ab)

The symbol ^ means the power of / your exponent. Hope this helps !!

4 0

3 years ago

{2x+2y=2,2(x+y)=10}A. single solution B. no solution C. infinite solutions

mixer [17]

To find the number of solutions of a system of linear equations you need to identify the slope (m) in each equation:

$y=mx+b$

-If the slope is the same in both lines the system has no solution

-If the slope is different in the lines the system has one solution

-If the equation are the same (incluided the value of b) the system has infinitely many solutions

You have the next equations:

$\begin{gathered} 2x+2y=2 \\ 2(x+y)=10 \end{gathered}$

Write the equations in slope-intercept form y=mx+b (solve for y).

First equation:

$\begin{gathered} 2y=-2x+2 \\ y=-\frac{2}{2}x+\frac{2}{2} \\ \\ y=-x+1 \end{gathered}$

Second equation:

$\begin{gathered} 2x+2y=10 \\ 2y=-2x+10 \\ y=-\frac{2}{2}x+\frac{10}{2} \\ \\ y=-x+5 \end{gathered}$ As the equations have the same slope m = -1, the system has no solution (the line doesn't cross each other)

5 0

2 years ago

a veterinarian needs to know animals weight in kilograms. if 20 pounds is about 9 kilograms and a dog weights 30 pounds, use a r

ahrayia [7]

For this case we have the following conversion:

20 pounds = 9 kilograms

To use the table what we must do is find another relationship that allows us to find the weight in kilograms for 30 pounds.

For example, half the weight in pounds is half the weight in kilograms.

Therefore, the given conversion is:

10 pounds = 4.5 kilograms

So, for 30 pounds, we multiply this last ratio obtained by three on both sides:

30 pounds = 13.5 kilograms

Then, the table is:

Pounds 10 20 30

kilograms 4.5 9 13.5

Answer:

Using the ratio table the dogs weight is:

30 pounds = 13.5 kilograms

3 0

3 years ago

Read 2 more answers

(3+3x)+(2x-8) whats the answer?

masha68 [24]

Answer:

5x-5 is the answer.

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Some one please help​

Some one please help