If I get 10 dollars a week how much money will I have saved up in 9-years I WILL GIVE 55 POINTS

Let
x-------> bags of <span>popcorn
</span>y-------> bags of hotdogs

we know that
2.50x+3y=200-------> equation 1
x=2y--------> equation 2

substitute 2 in 1

2.50*[2y]+3y=200--------> 5y+3y=200------> 8y=200-----> y=200/8
y=25
x=2y-----> x=2*25-----> x=50

the answer is
50 bags of popcorn
25 bags of hotdogs<span />

5 0

3 years ago

The current process has a mean of 2.50 and a std deviation of 0.05. A new process has been suggested by research. What sample si

Novay_Z [31]

Answer:

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

$n=(\frac{z_{\alpha/2} s}{ME})^2$ (2)

The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025,0,1)", and we got $z_{\alpha/2}=1.96$ , replacing into formula (2) we got:

$n=(\frac{1.96(0.05)}{0.02})^2 =24.01$

So the answer for this case would be n=25 rounded up to the nearest integer

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 for the sample

$\mu$ population mean (variable of interest)

$\sigma=0.05$ represent the population standard deviation

n represent the sample size (variable of interest)

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$

The margin of error is given by this formula:

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

And on this case we have that ME =0.02 and we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{z_{\alpha/2} s}{ME})^2$ (2)

The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025,0,1)", and we got $z_{\alpha/2}=1.96$ , replacing into formula (2) we got:

$n=(\frac{1.96(0.05)}{0.02})^2 =24.01$

So the answer for this case would be n=25 rounded up to the nearest integer

7 0

2 years ago