20 POINTS HELP!! <br> Find the value of x and y

An article reported that for a sample of 52 kitchens with gas cooking appliances monitored during a one-week period, the sample

kolbaska11 [484]

Answer:

a) $654.16-2.01\frac{164.55}{\sqrt{52}}=608.29$

$654.16+2.01\frac{164.55}{\sqrt{52}}=700.03$

And we can conclude that we are 95% confident that the true mean of Co2 level is between 608.29 and 700.03 ppm

b) $n=(\frac{1.960(175)}{25})^2 =188.23 \approx 189$

Step-by-step explanation:

Part a

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

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=52-1=51$

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: "=-T.INV(0.025,51)".And we see that $t_{\alpha/2}=2.01$

Replacing we got:

$654.16-2.01\frac{164.55}{\sqrt{52}}=608.29$

$654.16+2.01\frac{164.55}{\sqrt{52}}=700.03$

And we can conclude that we are 95% confident that the true mean of Co2 level is between 608.29 and 700.03 ppm

Part b

The margin of error is given by :

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

The desired margin of error is ME =50/2=25 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

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

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 $z_{\alpha/2}=1.960$ , and we use an estimator of the population variance the value of 175 replacing into formula (b) we got:

$n=(\frac{1.960(175)}{25})^2 =188.23 \approx 189$

6 0

3 years ago

Can someone plz plz plz help me with this( also the word that is cut off says Then

GREYUIT [131]

Answer:

1.

4^16

2.

3× 10^3

3× 10^2

3× 10^1

3× 10^0

3× 10^-1

3× 10^-2

3× 10^-3

7 0

3 years ago

There are four erasers but only three pencils write the ratio of erasers to pencils

iris [78.8K]

4:3
4 to 3
4/3
I wrote all the three ways

3 0

3 years ago

Enter an inequality that represents the phrase the sum of 1 and y is greater than or equal to 6. The inequality is y = 4 a solut

True [87]

Answer:

Inequality to represent given data is y ≥ 5.

No, y = 4 is not a solution, since 4 is not a value that falls within the domain of the solutions for the inequality.

Step-by-step explanation:

Enter an inequality that represents the phrase the sum of 1 and y is greater than or equal to 6. The inequality is y = 4 a solution.

i) therefore y + 1 ≥ 6

ii) therefore y ≥ 5

iii) No, y = 4 is not a solution, since 4 is not a value that falls within the domain of the solutions for the inequality.

3 0

3 years ago

HI can you help me with this problem?The quantity demanded x for a certain brand of MP3 players is 300 units when the unit price

Vlad [161]

The demand equation is P = -0.05x + 105

STEP - BY - STEP EXPLANATION

What to find?

<em>The demand equation.</em>

The following information is used to solve the problem.

If (x₁ , y₁) and (x₂, y₂) are any dinstinct points on a line a non-vertical line L, then the equation of the line that has a slope(m) and passes through the point (x₁ , y₁) is given by the formula below:

$y-y_1=_{}\frac{y_2-y_1}{x_2-x_1}(x-x_1)$

Assume p, be the unit price and x be the demand when the price is $p.

From the question given, when the unit price x = 300 units, the demand p = $90 and when the unit price x = 1300 units, the demand p = $40

This means the demand curve passes through the points (300, 90) and (1300, 40).

Assume the demand equation is linear, then the line of the equation passes through the points (300, 90) and (1300, 40).

Now;

y=p x₁ =300 y₁ = 90 x₂ = 1300 y₂=40

Substitute the values into the function and simplify.

$p-90=\frac{40-90}{1300-300}(x-300)$

Simplify the above.

$p-90=\frac{-50}{1000}(x-300)$ $p-90=-0.05(x-300)$

Open the parenthesis.

P- 90 = -0.05x + 15

Add 90 to both-side of the equation.

P = -0.05x + 15 + 90

P = -0.05x + 105

Hence, the demand function is P = -0.05x + 105

6 0

1 year ago

20 POINTS HELP!! Find the value of x and y