The average zinc concentration recovered from a sample of measurements taken in 36 different locations in a river is found to be 2.6 grams per milliliter. Find the 95% and 99% confidence intervals for the mean zinc concentration in the river. Assume that the population standard deviation is 0.3 gram per milliliter.

Answers

Answer 1

Answer:

The 95% confidence interval for the mean zinc concentration in the river is between 1.75 and 3.45 grams per milliliter.

The 99% confidence interval for the mean zinc concentration in the river is between 1.48 and 3.72 grams per milliliter.

Step-by-step explanation:

95% confidence interval:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.95}{2} = 0.025[/tex]

Now, we have to find z in the Ztable as such z has a pvalue of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.025 = 0.975[/tex], so Z = 1.96.

Now, find the margin of error M as such

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

[tex]M = 1.96\frac{2.6}{\sqrt{36}}[/tex]

[tex]M = 0.85[/tex]

The lower end of the interval is the sample mean subtracted by M. So it is 2.6 - 0.85 = 1.75 grams per milliliter.

The upper end of the interval is the sample mean added to M. So it is 2.6 + 0.85 = 3.45 grams per milliliter.

The 95% confidence interval for the mean zinc concentration in the river is between 1.75 and 3.45 grams per milliliter.

99% confidence level:

By the same logic as for the 95% confidence interval, we have that [tex]Z = 2.575[/tex]. So

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

[tex]M = 2.575\frac{2.6}{\sqrt{36}}[/tex]

[tex]M = 1.12[/tex]

The lower end of the interval is the sample mean subtracted by M. So it is 2.6 - 1.12 = 1.48 grams per milliliter.

The upper end of the interval is the sample mean added to M. So it is 2.6 + 1.12 = 3.72 grams per milliliter.

The 99% confidence interval for the mean zinc concentration in the river is between 1.48 and 3.72 grams per milliliter.


Related Questions

It has been observed that some persons who suffer acute heartburn, again suffer acute heartburn within one year of the first episode. This is due, in part, to damage from the first episode. The performance of a new drug designed to prevent a second episode is to be tested for its effectiveness in preventing a second episode. In order to do this two groups of people suffering a first episode are selected. There are 45 people in the first group and this group will be administered the new drug. There are 75 people in the second group and this group will be administered a placebo. After one year, 12% of the first group has a second episode and 14% of the second group has a second episode. Conduct a hypothesis test to determine, at the significance level 0.1, whether there is reason to believe that the true percentage of those in the first group who suffer a second episode is less than the true percentage of those in the second group who suffer a second episode.
A. [ z < -1.65, RHo].
B. [ z < -1.65 and z > 1.65, FRHo].
C. [z > 1.65, FRHo].
D. [z < -1.65 and z > 1.65, FRHo].
E. [z > -1.65 and z < 1.65, RHo].
F. None of the above.

Answers

Answer:

F. None of the above.

Step-by-step explanation:

Let the null and alternate hypothesis be

H0: p1 ≥ p2 against the claim Ha: p1 < p2

the significance level is 0.1

The critical region is z < z∝= 1.28

The test statistic is

Z= ( p^1-p^2)- (p1-p2)/√p1^q1^/n1 + p2^q2^/n2

Here n1= 45 ,   n2= 75

         p1= 0.12         p2= 0.14

         q1= 0.88        q2= 0.86

z= 0.12- 0.14/√0.12*0.88/45 +0.14*0.86/75

Z=  0.02/ √0.00235 + 0.00161

Z=  0.02/0.062891

z= 0.318

The calculated value of z= 0.318  lies in the critical region z < 1.28

therefore accept Ha.

All of the options are incorrect as the critical value for one tailed test for 0.1 is 1.28 .

A b c or d?? Lmk..Brainly

Answers

Answer:

28.3 (b)

Step-by-step explanation:

To solve circumference, you will need to use the equation C = 2 *pi* r

for this, we will use 3.14 for pi and the radius is 4.5 so this is how we need to solve it

C= 2 pi (4.5)             Solve 2*4.5

C= 9 pi                     Now we input 3.14 for pi and multiply

C= 9(3.14)

C= 28.26                  Now we round to the nearest tenth to get

C=28.3

Given the function f(x) = 4^x - 1, explain and show how to find the average rate of change between x = 1 and x = 4.

Answers

Answer:

84

Step-by-step explanation:

f(1)=4^1 - 1 = 3

f(4) = 4^4 - 1 = 255

rate of change = [tex]\frac{f(x_2)-f(x_1)}{x_2-x_1}[/tex]

(255 - 3) / (4 - 1) = 252 / 3 = 84

PLEASE HELP I DONT KNOW

Answers

Answer:

28 in.

Step-by-step explanation:

Since the right portion of the figure is a square, the unlabeled bottom must be the same as the top or 6 in., therefore just add up the pieces starting on the right side. (5 + 6 + 2 + 5 + 4 + 6 = 28)

the perimeter of a square field is 880m. Find it's area in hectares​

Answers

This is the answer hope it helps

The area of the square field is 4840 hectares.

What is perimeter of square?

Perimeter of the square is defined as addition the lengths of the square's four sides.

Perimeter of the square equation is 4a

Where, a is length of the square

Given data as :

Perimeter of the square field = 880 m

Side of the square = Perimeter/4

Side of the square = 880/4

Side of the square = 220 m

So, length of each side of the square is 220 m

Area of square = Side × Side

Area of square = 220 m  × 220 m

Area of square = 48400 square meters

Area of square = 48.4 square kilometers

As we know that 1 sq km = 100 hectares

So, 48.4 km = 48.4 × 100 = 4840 hectares

Hence, the area of the square field is 4840 hectares.

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I will give Brainliest
Please help me find the answer

Answers

Answer:

in the first traingle

sinC = 36/39 = 12/13

CosC= 15/39 = 5/13

TanA= 15/36=5/12

this is the values i didnt understand the question so i just find the values

in the second Triangle

SinA=2√5/5

CosA=√5/5

TanB= √5/2√5=1/2

cos 30 = √3/2

sin45=√2/2

tan60= √3

hopefully its helpful iam sorry i didnt understand what they mean in the question my engilish is bad

Sin of c. Sin'-1(36/39)=90

Cos of c cos'-1(15/39)=67.38

Tan of a tan'-1(15/36)=22.62

Sin of a sin'-1(2squarroot5/5)=63.43

Cos od a cos'-1(squareroot5/5)=63.43

Tan of b tan'-1(2squareroot5/squareroot5)=63.43

Cos30 is pie/6 or squareroot of 3 /2

Sin of 45 is pie/4 or squareroot2/2

Tan60 is pie/3 or squareroot3



Use
f(x)= 800 (1.32)x for 1-3
What is the intial amount?
What is the growth rate?
What is the growth factor?

Answers

So this in the exponential form of ab^x, where a is the y intercept, b is the growth factor(base) and x is your domain. From this, we can answer each question. The initial amount is 800, growth rate is 32% and factor is 1.32.


Happy learning!

The Unit Circle

What is cos 180°?

a. 0
b. 1
c. -1
d. 1/2

Please select the best answer from the choices provided

Answers

Answer:

C. -1

Step-by-step explanation:

I calculated it logically

Answer:

-1

Step-by-step explanation:

cos = opp/hyp

At 180º

adj  = -1

hyp = 1

Cos 180 = -1/1 = -1

Write an equation of a line with slope -4 and y- intercept of 0

Answers

Answer:

y=-4x

Step-by-step explanation:

Leta has $45 in her account in May. How much money does she have in her account in August

Answers

45-15= 30-28= 2+18=20
Is that what the question was asking??

The sidewalk is 5 feet wide and the garden measures 20 feet across. Which measurement is closest to the area of the outer edge of the sidewalk?
A.
200 ft2

B.
400 ft2

C.
700 ft2

D.
1,000 ft2

Answers

Answer:

A (obviously)

Step-by-step explanation:

Info Given

Sidewalk is 5 ft. wideGarden is 20 ft. across

Lemonade will be served in 8 oz cups. One pint=16 oz. How many cups of lemonade in 5 gallons

Answers

640
128 = 1 gallon times 5 equals 640

Answer:

80 cups

Step-by-step explanation:

1 gallon = 128 oz

5x128= 640 oz

640/8=80

The Sine Function

According to the National Weather Service, the average monthly high temperature in the Dallas/Fort Worth, Texas area from the years of 2006-2008 is given by the following table:

To get a feel for the relationship between the month and the average high temperatures, the data is plotted on the following scatter plot.

If the plot was extended to a two year period with 1 = Jan of the first year, 12 = Dec of the first year, 13 = Jan of the second year, 24 = Dec of the second year, describe the plot with the additional information.

a. Linear
b. Random dots
c. Wave-like and repetitive
d. Quadratic

Please select the best answer from the choices provided

Answers

Answer:

C. Wave-like and repetitive

Step-by-step explanation:

I calculated it logically

Four less than two times a number is seven times the sum of that number and 8. Which equation
could be used to solve this problem?

1. 4- 2n + 7n = 8
2. 2n - 4 = 7n + 8
3. 2n - 4 = 7(n + 8)
4. 4 - 2n = 7(n + 8)​

Answers

9514 1404 393

Answer:

  3.  2n - 4 = 7(n + 8)

Step-by-step explanation:

Two times a number is 2n. Four less than 2n is (2n-4). The sum of a number and 8 is (n+8). Seven times that sum is 7(n+8). The statement says these values are equal:

  2n -4 = 7(n +8)

Degree and Radian Measures

Convert the given radian measure to a degree measure.
1.2 /pi (π)

a. -216°
b. 108°
c. 216°
d. -108°

Please select from the best choices provided

Answers

Answer:

C. 216°

Step-by-step explanation:

I calculated it logically

Plz help find the rule 50 points

Answers

Answer:

1², 2²,3², 4², 5², 6², 7², 8², 9², 10², 11², 12², 13², 14², 15², 16², 17², 18², 19², 20²,........

Each number is multiplied by itself.

i got yelled at for my grandma giving a coney dog at A and W and she got sick is there a way i can cut my dad out of his life

Answers

Answer:

this whole sentence confused me a lot

Step-by-step explanation:

yes there is, but it depends on how you want to do it

Answer:

I don't really get what you're implying can you please explain?

Step-by-step explanation:

haha this just really confused me :)

Five times a number is 80 less than 7 times the number. Find the number.

Answers

I think its 16 but im not completly sure

Take a look at the photo and please right an explanation for your answer

Answers

The answer is 360

So you have to find the volume of the top part of the shape which is 72. Then you get the other parts, which is 288. Add them up and get 360

You deposit $800 in an account that pays 3.6% annual interest compounded quarterly. When does your balance first exceed $1200?

Answers

Answer:

It would take 4 years. The formula for continuously compounded interest is: where P is the principal, r is the interest rate as a decimal number, and t is the number of years.

Step-by-step explanation:

You deposit $800 in an account that pays 3.6% annual interest compounded quarterly. after 11 years your balance first exceed $1200.

How to find the compound interest?

If n is the number of times the interested is compounded each year, and 'r' is the rate of compound interest annually, then the final amount after 't' years would be:

[tex]a = p(1 + \dfrac{r}{n})^{nt}[/tex]

You deposit $800 in an account that pays 3.6% annual interest compounded quarterly.

[tex]a = p(1 + \dfrac{r}{n})^{nt}[/tex]

[tex]1200 = 800(1 + \dfrac{3.6}{4})^{4t}\\\\300 = (1 + 0.9)^{4t}\\\\t = 11.4[/tex]

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I do need to know NOTHING.

Answers

Answer:

Thats cool man.

Step-by-step explanation:

2.247 divided into 7 equals what​

Answers

I think it’s 200.000

Suppose that two investors A and B have exhibited the indifference probabilities as shown in table below. Indifference probability Investor A Investor B Net return (RM) -2000 0 0 - 1000 0.70 0.10 0 0.80 0.20 1000 0.85 0.30 2000 0.90 0.50 3000 0.95 0.60 4000 1.00 1.00 a) Determine the utility value (for each monetary value) for each investor and fill it in table above. b) Graph the utility functions for both investors and categorize each investor as either a risk- averse person or a risk seeker. c) Suppose that investor A has the chance to invest in one of two ventures. Venture I can produce a net return of RM3000 with probability 0.40 or a net loss of RM1000 with probability 0.60. Venture II can produce a net return of RM2000 with probability 0.60 and no return with probability 0.40. Based on utility function in (b), use the expected utility criterion to determine the venture investor A should select. What is the expected monetary value associated with the selected venture?

Answers

Answer:

Da Answer is Suppose that two investors A and B have exhibited the indifference probabilities as shown in table below. Indifference probability Investor A Investor B Net return (RM) -2000 0 0 - 1000 0.70 0.10 0 0.80 0.20 1000 0.85 0.30 2000 0.90 0.50 3000 0.95 0.60 4000 1.00 1.00 a) Determine the utility value (for each monetary value) for each investor and fill it in table above. b) Graph the utility functions for both investors and categorize each investor as either a risk- averse person or a risk seeker. c) Suppose that investor A has the chance to invest in one of two ventures. Venture I can produce a net return of RM3000 with probability 0.40 or a net loss of RM1000 with probability 0.60. Venture II can produce a net return of RM2000 with probability 0.60 and no return with probability 0.40. Based on utility function in (b), use the expected utility criterion to determine the venture investor A should select. What is the expected monetary value associated with the selected venture?

Step-by-step explanation:

LESSSSSSS GOOOOOOOOOO

All of the following are equivalent except _____.
7.5:4.5
5 is to 3
15/5
45/27

Answers

Answer:

15/5

Step-by-step explanation:

because 7.5 ÷ 4.5 = 1.66667

5 ÷ 3 = 1.66667

and 45 ÷ 27 = 1.66667

but 15 ÷ 5 = 3 therefore it's the off one out.

round 98,376 to the nearest thousand

Answers

Answer:

98000

Step-by-step explanation:

What is the mean ? 50, 55, 58, 58, 90, 92, 99

Answers

sum of observations

mean =..........................

no. of observations

50+55+58+90+58+92+99 502

....................................... = .........= 71.7

7 7

awnser is 71.7

hope this helped

Simplify.

4^3•4^-6

A. 1/4^3
B. 1/4^9
C. 1/4^18
D. 4^3

Answers

Answer:

A

Step-by-step explanation:

This can be rearranged as 4^3 * 1/(4^6)

or (4^3)/(4^6)

This can be changed to:

(4^3)/((4^3)*(4^3)

Which is equal to 1/(4^3)

or

4^(-3)

Is the equation a linear function?
y = -x + 3

Answers

Answer:

x=3

Step-by-step explanation:

y=-x+3

0=-x+3

x=3

I really hope you guys will help me

Answers

Answer:

I think its

ai. fx-f3

ii. 5gx

Help please!!!! will Brainly!!!

Answers

Answer:

true

Step-by-step explanation:

.................

True :) have a nice day! :) can u make me brainliest? Pls :)? Ty ✨
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