Using graphite furnace atomic absorption spectrometry, the mean cadmium (cd2 ) content value in a homogenized sample of 40 zebra mussles was found to be 7.50 ppb cd2 with a standard deviation (s) of 0.52 ppb cd2 (assume that s is a good approximation of σ). calculate the 90% and 95% confidence intervals (ci) for: (a) two analyses and (b) five analyses of this homogenized sample.

Answers

Answer 1

Part A1:

Given that the mean cadmium (cd2 ) content value in a homogenized sample of 40 zebra mussles was found to be 7.50 ppb cd2 with a standard deviation (s) of 0.52 ppb cd2

The 90% confidence interval for a sample of size n, with sample mean [tex](\bar{x})[/tex] and a standard deviation of s is given by:

[tex]90\%\ C.I.=\bar{x}\pm1.645\left( \frac{s}{ \sqrt{n} } \right)[/tex]

Thus, the 90% confidence intervals (ci) for two analyses is given by:

[tex]7.50\pm1.645\left( \frac{0.52}{ \sqrt{2} } \right)=7.50\pm1.645(0.3677) \\ \\ =7.50\pm0.6049=(6.90, \ 8.1)[/tex]

Part A2:

Given that the mean cadmium (cd2 ) content value in a homogenized sample of 40 zebra mussles was found to be 7.50 ppb cd2 with a standard deviation (s) of 0.52 ppb cd2

The 95% confidence interval for a sample of size n, with sample mean [tex](\bar{x})[/tex] and a standard deviation of s is given by:

[tex]95\%\ C.I.=\bar{x}\pm1.96\left( \frac{s}{ \sqrt{n} } \right)[/tex]

Thus, the 95% confidence intervals (ci) for two analyses is given by:

[tex]7.50\pm1.96\left( \frac{0.52}{ \sqrt{2} } \right)=7.50\pm1.96(0.3677) \\ \\ =7.50\pm0.7207=(6.78, \ 8.22)[/tex]

Part B1:

Given that the mean cadmium (cd2 ) content value in a homogenized sample of 40 zebra mussles was found to be 7.50 ppb cd2 with a standard deviation (s) of 0.52 ppb cd2

The 90% confidence interval for a sample of size n, with sample mean [tex](\bar{x})[/tex] and a standard deviation of s is given by:

[tex]90\%\ C.I.=\bar{x}\pm1.645\left( \frac{s}{ \sqrt{n} } \right)[/tex]

Thus, the 90% confidence intervals (ci) for five analyses is given by:

[tex]7.50\pm1.645\left( \frac{0.52}{ \sqrt{5} } \right)=7.50\pm1.645(0.2326) \\ \\ =7.50\pm0.3825=(7.12, \ 7.88)[/tex]

Part B2:

Given that the mean cadmium (cd2 ) content value in a homogenized sample of 40 zebra mussles was found to be 7.50 ppb cd2 with a standard deviation (s) of 0.52 ppb cd2

The 95% confidence interval for a sample of size n, with sample mean [tex](\bar{x})[/tex] and a standard deviation of s is given by:

[tex]95\%\ C.I.=\bar{x}\pm1.96\left( \frac{s}{ \sqrt{n} } \right)[/tex]

Thus, the 95% confidence intervals (ci) for five analyses is given by:

[tex]7.50\pm1.96\left( \frac{0.52}{ \sqrt{5} } \right)=7.50\pm1.96(0.2326) \\ \\ =7.50\pm0.4559=(7.04, \ 7.96)[/tex]

Related Questions

Roni and Allie are mowing the grass at the soccer field. Roni has a riding lawn mower and can mow the field in 30 minutes. Allie is pushing a lawn mower and can mow the field in 75 minutes.
If Roni and Allie work together to mow the field, what part of the field would Roni mow?
A. about 0.52 of the field
B. about 0.64 of the field
C. about 0.71 of the field
D. about 0.87 of the field

Answers

Roni would mow about 0.71 of the field.

Answer: C. about 0.71 of the field

Step-by-step explanation:

Since, Roni can mow the field in 30 minutes.

Thus, the work done by Roni in one day = 1/30

And, Allie can mow the field in 75 minutes.

Thus, the work done by Allie in one day = 1/75

⇒ The total work done by Roni and Allie in one day when they worked simultaneously,

= [tex]\frac{1}{30} + \frac{1}{75}[/tex]

= [tex]\frac{5}{150} + \frac{2}{150}[/tex]

= [tex]\frac{7}{150}[/tex]

[tex]\implies \text{The part of work done by Roni} = \frac{\text{the work done by her in one day}}{\text{Total work they done in one day}}[/tex]

[tex]= \frac{1/30}{7/150}[/tex]

[tex]= \frac{5}{7}=0.714285714\approx 0.71[/tex]

⇒ Option C is correct.

How to find the other endpoint with the given endpoint and midpoint?

Answers

To find the other endpoint with a given endpoint and midpoint, you subtract the midpoint values from the endpoint, then with whatever the answer is, you subtract that from the midpoint.

mixed number change into a improper fraction 3 9/12 + 6 1/2 show ur work

Answers

3 9/12= 3 3/4
3 3/4= 15/4

6 1/2= 13/2
13/2(2/2)= 26/4

15/4+ 26/4= 41/4

The answer is 41/4 or 10 1/4.

Hope this helps!

Answer 1 1/4. first for 3 9/12 you multiply 12 x 3 + 9 same for 6 1/2. then add. then make it into a mixed fraction again.

------Seventh Grader

The equation of a parabola is given.y=1/8x^2+4x+20 What are the coordinates of the focus of the parabola?

Answers

he equation of a parabola is x = -4(y-1)^2. What is the equation of the directrix?
You may write the equation as
(y-1)^2 = (1) (x+4)
(y-k)^2 = 4p(x-h), where (h,k) is the vertex
4p=1
p=1/4
k=1
h=-4

The directrix is a vertical line x= h-p
x = -4-1/4
x=-17/4

-------------------------------
What is the focal length of the parabola with equation y - 4 = 1/8x^2
(x-0)^2 = 8(y-4)
The vertex is (0,4)
4p=8
p=2 (focal length) -- distance between vertex and the focus
-------------------------------
(y-0)^2 = (4/3) (x-7)
vertex = (7,0)
4p=4/3
p=1/3
focus : (h+p,k)
(7+1/3, 0)

Convert it to vertex form we get

y = 1/8(x + 16)^2 - 12

so the vertex is at (-16,-12) and the x coordinate of the focus will be -16)

The focus will be at (-16, k + p) Here k = -12 from the vertex equation and p = 1 / 4a where a = 1/8 so p = 1 / 1/2 = 2 So k + p = -12 + 2 = -10

So the coordinates of the focus are (-16, -10) answer

m=(x+n)/(p)

An answer would be sweet!! God bless

Answers

The answer to your problem is:

x=-n+mp

Sawyer’s mom paid $1.50 for a 3/4 pound box of cereal. How much is that per pound?

A.$1.50
B.$1.75
C.$2.00
D.$2.50

Answers

the answer is c hope I helped

I believe the answers C

Why does the limit as x approaches zero for the function f(x)=sin(π/x) not exist?

limx→0 sin(π/x)

Answers

as x approaches 0, pi/x approaches infinity
that would be sin(infinty) which is nonexistant because it goes up and down and doesn't approache a value

PLEASE HELP ME IN THESE TWO QUESTIONS ASAP! AND YES, I AM GOING TO MARK YOU AS THE BRAINLIEST ANSWER!!!!!

Answers

The line from the point to its reflection should be perpendicular.If we imagine a line from (5,7) to (2,2), it would have a slope of (2-7)/(2-5) = 5/3.

For that line to be perpendicular to y=-2/5x+6, their slopes should be each other's negative reciprocals.

-2/5 negative reciprocal is 5/2, which is not equal to our calculated 5/3, so (2,2) cannot be the reflected point. Evan was wrong.

Q1-74: AB have slope 6/5, C has -5/6, D 6/5, E -5/6 again.

Use the premises and conclusion to answer the questions.

Premises:
If a quadrilateral has two pairs of parallel sides, then it is a parallelogram.
If a quadrilateral is a parallelogram, then its opposite angles are congruent.

Conclusion:
If a quadrilateral has two pairs of parallel sides, then its opposite angles are congruent.

Which statement best describes this argument?

The argument is valid by the law of syllogism.

The argument is invalid because the conclusion does not follow the premises.

The argument is valid by the law of detachment.

The argument is invalid because the premises are not true.

Answers

Answer:

The argument is valid by the law of syllogism.

Step-by-step explanation:

The law of syllogism is also called the law of transitivity. It is based on the transitive property, which states "if a = b and b = c, then a = c."

In our problem, our statement a would be "A quadrilateral has two pairs of parallel sides". Our statement b would be "It is a parallelogram." Our statement c would be "Its opposite angles are congruent."

That would make "if a = b"

"If a quadrilateral has two pairs of parallel sides it is a parallelogram."

Then "b = c" would be

"If a quadrilateral is a parallelogram, its opposite angles are congruent."

"a = c" would then be

"If a quadrilateral has two pairs of parallel sides its opposite angles are congruent."

This is the conclusion we were given, so this is the law of syllogism.

Write an equation of an ellipse with vertices of (-3, 0) and (3, 0), and co-vertices (0, -5) and (0, 5). Graph the ellipse.

Answers

This graph is the answer:

Which of the symbols does not make the following statement true?

|-1| ___ |1|

>
≤
≥

Answers

The less than or equal to symbol (the symbol in the middle)

Bob did one random math fact on the first day, two random math facts on the second day, three random math facts on the third day, and so on. On which day will he do his 97th random math fact?

Answers

it will be on the 14th day.

See attached picture:

Answer:

on the 14th day

Step-by-step explanation:

Please help me with this!!!

Answers

If y varies inversely as x, this means there is some value k such that:
[tex]y=\frac{k}{x}[/tex]

Using the given information, we can find k:
[tex]39=\frac{k}{3}[/tex]
[tex]39*3=k[/tex]

So then k=117. Now we just need to solve for y when x=11:
[tex]y=\frac{117}{11}[/tex]

A total of 231 tickets were sold for the school play. They were either adult tickets or student tickets. The number of student tickets sold was two times the number of adult tickets sold. How many adult tickets were sold?

Answers

well if there are 231 tickets, then divide 231 by three, that will equal 77, so if you see what i am doing,i am diving all tickets by 3 so that the students get 2/3 and the adults get the pther 1/3. so the answer is 77.

Final answer:

To determine the number of adult tickets sold for the school play, an equation was set up using algebra with x representing adult tickets, which turned out to be 77 after solving the equation x + 2x = 231.

Explanation:

The student has asked to find out how many adult tickets were sold when a total of 231 tickets were sold for a school play, with the number of student tickets being two times the number of adult tickets. To solve this, we can use algebraic methods and set up an equation.

Let x be the number of adult tickets sold, then the number of student tickets sold would be 2x. Given that the total number of tickets is 231, we can write the equation as:

x + 2x = 231

Simplifying, we get:

3x = 231

Dividing both sides by 3, we find that:

x = 77

Therefore, 77 adult tickets were sold.

Sue has 18 sweets. tony has 18 sweets.sue gives tony x sweets. Sue then eats 5 sweets. Tony then eats half of his sweets. Write expressions for the number of sweets sue and tony have now

Answers

The expressions for the number of sweet Sue and Tony have are 13 - x and

18 + x / 2 respectively

Sue has 18 sweet.

Tony has 18 sweet.

Sue gives Tony x sweet . Sue sweet will be

18 - x

Sue then eats 5 sweets then his sweet will be

18 - 5 - x = 13 - x

Tony collected x sweet from Sue. His sweet will be

18 + x

Tony ate half of his sweets . His remaining sweet will be

18 + x / 2

The expression for Sue sweets is : 13 - x

The expression for Tony sweets is : 18 + x / 2

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Expressions for the number of sweets sue and tony have now :

Sue: 13 - x sweets

Tony: (3/2)x + 18 sweets

Here are the expressions for the number of sweets Sue and Tony have now:

Sue: 18 - x - 5 = 13 - x

Tony: 18 + x - (1/2)x = (3/2)x + 18

Here's a breakdown of the calculations:

Sue's sweets:

Sue starts with 18 sweets.

She gives Tony x sweets.

She then eats 5 of her sweets.

Therefore, Sue now has 18 - x - 5 sweets, which can be simplified to 13 - x.

Tony's sweets:

Tony starts with 18 sweets.

Sue gives him x sweets.

He then eats half of his sweets.

Since Tony eats half of his sweets, he is left with (1/2) of his sweets. Therefore, Tony now has 18 + x - (1/2)x sweets, which can be simplified to (3/2)x + 18.

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Can someone Please help me? How did I get this question wrong? I chose the last option, but that's incorrect. Please answer asap. Most helpful answer gets brianliest!

The triangle JKL shown on the coordinate grid below is reflected once to map onto triangle J'K'L':
If vertex L' is at (−3, 4), what are the coordinates of vertex J'?

(1, −8)

(−8, 1)

(−1, 8)

(8, −1)

Answers

(-8,1) it being reflected to the other side so just move the points

The coordinates of J are (8, 1), so J' is (-8, 1).

To the nearest tenth, find the perimeter of ∆ABC with vertices A(2,4), B(-2,1) and C(2,1). Show your work.

Answers

First, we should calculate the lengths of the three sides (see the figure below).

The distance between two coordinates (x₁, y₁) and (x₂, y₂) is given by the formula
[tex]d= \sqrt{(x_{2}-x_{1})^{2}+(y_{2}-y_{1})^{2}} [/tex]

Because the triangle is a right angle (indicated by the figure), we can determine the lengths of BC and AC easily.
The length of BC is the change in the x-coordinates, and AC is the change in the y-coordinates.
BC = 2 - (-2) = 4
AC = 4 - 1 = 3

To find AB, use the distance formula (the same as the Pythagorean theorem).
AB = √[(2-(2)) ²+ (4-1)² ] = √(4²+3²) = √25 = 5

The area of the triangle is (1/2)*BC*AC = (1/2)*4*3 = 6

Answer: 6

In a pet store the number of fish is 120 more than three times the number of reptiles. If the pet store has 210 fish, how many reptiles does it have? Write a two step equation to model the scenario. Then solve the question.

Answers

Let r represent reptiles
210=3r-120
330=3r
110=r

110 reptiles

Answer:

110

Step-by-step explanation:

What's the greatest common factor of 45,9,63

Answers

The greatest common factor of those numbers is the largest number that you can divide each of those numbers by. Looking at those three numbers, we can see that all three can be divided by 9. We also know that there is now way to divide those numbers evenly by a greater number than 9, because 9 is one of our options, and if we divided 9 by any number greater than 9, we would not get a whole number.

Answer:

GCF = 9

Step-by-step explanation:

Miguel received a $50 gift card to the bookstore. he would like to buy 3 books that cost$ 15.75 each including tax. he estmates that he cannot bey all three book because each book cost about $20, and all three book would cost $60 .is his estimate resonable?explain your reasoning.

Answers

yes his answer is correct because if you round the answer to the nearest tenth it would make it a close answer to Miguel if you need this explained better let me know

yes because 3×20=60 DAH!

The measure of ∠AKG is 133°.

What is m∠AKD?

Enter your answer in the box.
m∠AKD =

Answers

mes ∠AKG = mes ∠AKD + mes ∠ DKG

133° = mes ∠ AKD + 87°

133° - 87° = mes ∠AKD

∠AKD = 46°

Final answer:

To find m∠AKD, subtract the measure of ∠AKG from 180 degrees.

Explanation:

To find the measure of ∠AKD, we need to use the fact that the sum of the measures of angles in a triangle is 180 degrees. Since we know that ∠AKG is 133 degrees, we can subtract this from 180 to find the remaining angle.

180 - 133 = 47 degrees

Therefore, m∠AKD = 47 degrees.

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sharon drives 3 miles to every 2 miles driven by steve how far does sharon drive if the journey is 250 miles

Answers

divisor = 3+2 = 5
250 / 5 = 50

so sharon drives 3*50 = 150 miles and steve drives 100.

3 x 250=750
750/2=375

In 2003, the population of an african country was about 12 million people, which is 3 million more than 2 times the population in 1950. enter and solve an equation to find the approximate population p (in millions) in 1950. an equation is . the approximate population in 1950 was million people.

Answers

12 = 2p + 3
12 - 3 = 2p
9 = 2p
9/2 = p
4.5 = p......so the population in 1950 was approximately 4.5 million people

Answer:

3 million

Step-by-step explanation:

The iq scores of the five members of the duluth family are 100, 82, 104, 96, and 118. for this distribution of scores, the range is:

Answers

The range is the difference between the biggest and smallest number.

Let R = range

R = 118 - 82

R = 36

The range is 36.

Final answer:

The range of the IQ scores (100, 82, 104, 96, and 118) for the Duluth family is calculated by subtracting the lowest score from the highest (118 - 82), resulting in a range of 36 points.

Explanation:

The IQ scores of the five members of the Duluth family are 100, 82, 104, 96, and 118. To find the range of this distribution of scores, you first identify the highest and lowest scores in the set. The highest IQ score is 118, and the lowest is 82. The range is the difference between the highest and lowest scores, so:

Range = Highest score - Lowest score

Range = 118 - 82

Range = 36

Therefore, the range of the distribution of IQ scores for the Duluth family is 36 points.

what is the solution of x^2+x-6≤0?

Answers

1) Factor the polynomial

x^2 + x - 6 = (x + 3) (x - 2)

So, can solve (x + 3)(x - 2) ≤ 0

The condition for the product of two factors be zero or negative is that the both are zero or have different signs (one positive and the other negative)

a) when x + 3 ≤ 0 and x - 2 ≥ 0

x + 3 ≤ 0 => x ≤ - 3

x - 2 ≥ 0 => x ≥ 2

Given that it is imposible that x be less or equal tha - 3 and greaer or equal than 2, this solution is empy.

b) when x + 3 ≥ 0 and x - 2 ≤ 0

x + 3 ≥ 0 => x ≥ - 3

x - 2 ≤ 0 => x ≤ 2

Solution: - 3 ≤ x ≤ 2 or [-3,2]

∠A and ∠B are vertical angles with m∠A=x and m∠B=3x−60 . What is m∠A ? Enter your answer in the box.

Answers

Did u find out the answer?

we know that

Vertical angles are congruent angles opposite each other where two lines cross

in this problem

m∠A=m∠B

substitute the values

[tex]x=3x-60\\3x-x=60\\2x=60\\x=60/2\\x=30\°[/tex]

therefore

the answer is

The measure of angle A is [tex]30\°[/tex]

A football team lost 5 yards on one play and gained 12 yards on the next play. write a sum of integers to find the overall change in field position. explain your answer

Answers

lost 5 then gained 12....
-5 + 12 = 7...overall change is 7

assume f(x)=4x+8 and g(x)=5. what is the value of (golf)(-1)

idk what is it, show work plz?

Answers

The answer is 5. The question wants you to compose the functions to get g(x) composed of f(x). Typically, when composing functions your substitute the second function into the first function in place of x. However, the function g(x) is constant at 5 since it has no x values. g(x)=5 means that g(x) is 5 at all values of x. Thus, in this case, it doesn't matter that we are doing a composition because the top-level function is g(x) and g(x) is 5 no matter what.

Which figures are polygons? Figure A has 6 sides all made of line segments. figure b is a regular hexagon. it has 6 sides made all of segments. Figure c is shaped iike a long semicircle. the bottom is a segment. The top part is curved. Figure D has 7 sides which are all segments.

Answers

A polygon is a closed figure made by joining line segments, where each line segment intersect exactry two other line segments.

A polygon is said to be a regular polygon if the sides are all of the same length.

Thus, the figures that are polygon are:

Figure A which has 6 sides all made of line segments.

Figure B which is a regular hexagon, having 6 sides made all of segments.

Figure D has 7 sides which are all segments.

Answer:

A,B,D

Step-by-step explanation:

i go to k-12 and the answer is correct

Which conversion factors can be used to multiply to 4 km/min to get meters per hour?

Select each correct answer.

A. 1 h60min

B. 1000 m1 km

C. 1 km1000 m

D. 60min1 h

Answers

From what I'm getting is that the right answer is either A or D I dont know yet but I'm getting that answers

Answer: the answer is B and D

how i know i took a test and it said thes are the anwer

hope this helps you out you a lot

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