Answer only if you know and NOT because you want brainliest ( ill report you if you do )

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

2 years ago

Question 3 (20points)<br> Solve the quadratic equation using the quadratic<br> -x2+8x=7

Angelina_Jolie [31]

Answer:

x = 7 or x = 1

Step-by-step explanation:

For this equation: a=-1, b=8, c=-7

−1x2+8x+−7=0

Step 1: Use quadratic formula with a=-1, b=8, c=-7.

x= ( −b±√b2−4ac )/2a

x= (−(8)±√(8)2−4(−1)(−7))/ (2(−1) )

x= (−8±√36 )/-2

x=1 or x=7

3 0

2 years ago

River rambler charges $25 per day to rent a kayak. How much will it cost to rent a kayak for 5 days? Write and solve an equation

Sati [7]

Answer:

C=25d

Step-by-step explanation:

We write an equation where C or cost is my output and d or days is my input. I should be able to put in any number of days and find the cost. Let's gather some data:

River Ramble

Day 1 $25(1)=25 cost

Day 2 $25(2)=50 cost

Day 3 $25(3)=75 cost

Day d $25(d)=C.

Our equation is C=25d.

5 0

3 years ago

Stock valued at $49.50 decreases in value by 12% each year. How much will the stock be worth in 5 years? Round your answer to th

bearhunter [10]

Answer:

Step-by-step explanation:

f(5)=49.5(0.88)^5

f(5)=$26.12

6 0

2 years ago

Is the answer 2 to this question?

iragen [17]

Answer:

its 8

Step-by-step explanation:

use ratio solution ..

2 shampoo : 9 water

8 shampoo : 36 water

9x4 = 36

same goes too shampoo.. it needs to be multiplied with 4 as to get 36 water u multiplied 9 with 4

6 0

2 years ago

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