11. Twelve samples of water form a particular source have an average lead concentration of 12.5µg/L with a standard deviation of 2.0µg/L. 1 (a) Find a 95% confidence interval for the lead concentration in water from this source. (b) Can you conclude that the lead concentration is less than 14µg/L?

Answers

Answer 1

Answer:

a) The 95% confidence interval for the lead concentration in water from this source is between 11.23 µg/L and 13.77 µg/L.

b) The upper bound of the confidence interval is less than 14 µg/L, which means that yes, we can conclude that the lead concentration is less than 14µg/L.

Step-by-step explanation:

We have the standard deviation for the samples, which mean that the t-distribution will be used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 12 - 1 = 11

95% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 11 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 2.201

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.201\frac{2}{\sqrt{12}} = 1.27[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 12.5 - 1.27 = 11.23 µg/L.

The upper end of the interval is the sample mean added to M. So it is 12.5 + 1.27 = 13.77 µg/L.

The 95% confidence interval for the lead concentration in water from this source is between 11.23 µg/L and 13.77 µg/L.

(b) Can you conclude that the lead concentration is less than 14µg/L?

The upper bound of the confidence interval is less than 14 µg/L, which means that yes, we can conclude that the lead concentration is less than 14µg/L.


Related Questions

You work and your hourly wage is $12.25 if you work 40 hours this week ,how much money would you make before taxes?

Answers

Answer:

$490

Step-by-step explanation:

Since one hour of work is $12.25, 40 hours is $490.

12.25 x 40 = 490

------------------

John 8:12 - Jesus spoke to the people once more and said, “I am the light of the world. If you follow me, you won’t have to walk in darkness, because you will have the light that leads to life.”

Philippians 2:7-8 - but emptied Himself, taking the form of a bond-servant, and being made in the likeness of men. Being found in appearance as a man, He humbled Himself by becoming obedient to the point of death, even death on a cross.

What’s the volume of each cylinder

Answers

Answer:

471.24 is cylinder A

282.74 is cylinder B

Step-by-step explanation:

https://www.calculator.net/volume-calculator.html

here's the calculator I used.

What is the simplified value of the expression below?

StartFraction 7 times 8 + 20 (4.5) over 16 times 0.5 EndFraction
18.25
21.38
110.25
119.50

Answers

Answer:

C: 110.25

Step-by-step explanation:

The simplification form of the provided expression is 18.25 option (A) is correct.

What is an expression?

It is defined as the combination of constants and variables with mathematical operators.

We have a mathematical expression:

[tex]= \rm \dfrac{7\times8+20(4.5)}{16\times0.5}[/tex]

= (56 + 90)/8

= 146/8

= 18.25

Thus, the simplification form of the provided expression is 18.25 option (A) is correct.

Learn more about the expression here:

brainly.com/question/14083225

#SPJ2

40 POINTS !! 40 POINTS !!

PLEASE HELP , DONT SKIP !

NO LINKS OR FILES.

Answers

Don’t mind the equation above the plot. Hope this helps:)

Answer:

2 0 4 3 1.

Step-by-step explanation:

u mean 10 points

if GameStop buys a video game for $35.00 and sells it with a 15% markup. How much does it cost the customer?

Answers

Answer:

40.25$

Step-by-step explanation:

PLEASEEEE HELP I WILL MAKE YOU BRAINIEST

Answers

Answer:

14

Step-by-step explanation:

Because right angles are 90 degrees, we need to subtract 34 from 90 which gets us 56. That means 56 = 4x, so 56/4 = 14, therefore X = 14.

Hope this helps!

Both angles form a right angle which is 90 degrees.

Angle 2 would equal 90 degrees - angle 1

Angle 2 = 90 -34 = 56

So now we know 4x = 56

To find x divide both sides by 4

X = 14

Which of the equations below could be the equation of this parabola?

Answers

Answer:

The correct answer is C

Your welcome:)

The equation below could be the equation of this parabola is y = -5x².

Option A is the correct answer.

What is a parabola?

A parabola is an equation of a curve, such that any point on the curve is equidistant from a fixed point called the focus and a fixed line called the directrix of the parabola.

The equation of a parabola:

y = a(x - h)² + k

We have,

Since the parabola vertex is at (0,0) and is open to the left, the equation of the parabola must be of the form:

y = a x², where a is a positive constant.

Now,

The only equation that fits this form is y = -5x².

Thus,

The equation below could be the equation of this parabola is y = -5x².

Learn more about parabola here:

https://brainly.com/question/21685473

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For each of the following studies, say whether you would use a t test for dependent means or a t test for independent means.

a. A researcher randomly assigns a group of 25 unemployed workers to receive a new job skills program and 24 other workers to receive the stan- dard job skills program, and then measures how well they all do on a job skills test.
b. A researcher measures self-esteem in 21 students before and after taking a difficult exam.
c. A researcher tests reaction time of each member of a group of 14 individuals twice, once while in a very hot room and once while in a normal- temperature room.

Answers

Answer:

1. T test for independent means

2. T test for dependent means

3. T test for dependent means

Step-by-step explanation:

In number 1, the two groups are unrelated. The first group has 25 subjects and they're all unemployed. The second group has 24 subjects and their employment status is not stated and might not be the same all through. Also, the first group is receiving a new type of job skills program while the second group is taking the standard job skills program.

- The groups in the experiment are unrelated

- The tests in the research are unrelated

- The purpose of the research is unreasonable - the researcher seeks to measure how well all 49 subjects perform on 'a' job skills test! No comparison between the scores or mean scores of the two groups.

In number 2, the researcher uses the same subjects and also measures the same variable but twice. This is a good example of a study where the t test for dependent means can be taken. Same applies in case 3.

How does the stimulus check impact society please help me please i really need help please

Answers

Answer:

The stimulus check impacts society because it helps people or rather encourages people to invest. Not only individuals but also businesses. It also shows how the stimulus check gives more than peoples incomes. Not everyone can get the stimulus check, only tax payers who pay taxes every year and have a public job. This impacts society because not everyone can get the stimulus check, and some people receive lots of money and other people might get just a little. At the end of the day, it all depends on how much taxes you are paying each year and which job you have.

Hope this helps! :)

Find the product. 2 (-5)

Answers

Answer:

-10

Step-by-step explanation:

Answer:

-10

Step-by-step explanation:

a positive times a negative is a negative number

and 2 x 5 is 10

so it`s -10

PLS HELP THIS IS TRIGONOMETRY!!!! PLS SHOW STEPS

Answers

Answer:

third side =√{30²+16²)=34

sin theta/2=16/34

theta/2=sin-¹(16/34)

theta=28.07×2=56.14

Convert 562 hectograms to pounds to the nearest hundredth

Answers

Answer:

Is that your answer

Answer:

123.90

Step-by-step explanation:

1 Hectogram = 0.22 lbs

[tex]562*0.22=123.90\\[/tex]

Is (4, 3) a solution to the inequality 7x + 5y = 15?
yes
no

Answers

Answer:

no

Step-by-step explanation:

7x+5y=15

(x,y)

(4,3)

put in 4 for x and 3 for y

7(4)+5(3)=15

43=15

This equation is impossible

Hope that helps :0

Step-by-step explanation:

7x+5y=15 (x=4,y=3)

7(4)+5(3)=15

28+15=15

43>15

they are no equal

follow me

PLEASE HELP ME W THIS

Answers

9514 1404 393

Answer:

  (b)  C = dπ

Step-by-step explanation:

The irrational value π is the ratio between the circumference of a circle and its diameter. That is ...

  π = C/d

Rearranging to get a formula for the circumference, we have ...

  C = dπ

If your bank offered you 3% interest on $5,000 in your savings account, how much money would you have in your account at the end of the year after interest?

Answers

Answer:

$150

Step-by-step explanation:

The formula we'll use for this is the simple interest formula, or: I= p * r * t

Simplify (-3/5) divided by (7/6)

Answers

-18/35 is the answer to (-3/5) divided by (7/6)

what is the radius of a sphere whose surface area is 100cm²?

Answers

Answer:

r≈2.82

Step-by-step explanation:

Hope this helps and have a great day!!!

Step-by-step explanation:

that can help you

Y=1/4 x + 2 which is the equation of a line parallel to the line with the equation

Answers

The answer is y=1/4x

Write and solve an equation to determine the height of a rectangular prism
with a width of 6 millimeters, a length of 20.5 millimeters, and a volume
of 984 cubic millimeters.

PLEASE HELP

Answers

Answer/Step-by-step explanation:

H = V/lw

H = 984/20.5*6

H = 984/128

H = 8

ANSWER:

H = 8

Model with mathematics. Abbi has decided to
offer a 2-hour computer gaming party for her
students. She can rent the student center for $45
per hour, and she can have the technology team set
up a network for up to 10 computers for a total of
$200 for the evening. Compose function p(x) such
that x is the number of students and p(x) is the
price per student for her to break even on the cost.
Note any appropriate restrictions on the domain x.

Answers

Answer:

180,000

Step-by-step explanation:

You got to multiply all the numbers and then divide by 600 and then you het your anwser

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Answers

These boys r annoying frfr like stop

Answer:

208

Step-by-step explanation:

Delta math

Jason built a model of the Pentagon for a social studies project. He made each outside wall 33 centimeters long. What is the perimeter of Jason’s model pentagon?

Answers

Answer:

165 centimeters

Step-by-step explanation:

A pentagon has 5 sides

Each side is 33 centimeters long

5 x 33 = 165

please help me someone i really need this to get my grade up :(

Answers

Answer: D

2 1/2 divided by 1/4 = 10

hope this gets ur grade up keep trying ur best!! :D

Which of the following is the solution to ?

Answers

Answer:

Could you add more info?

Step-by-step explanation:

110 calories
5 gummy bears
What is the unit rate per gummy bear?

Answers

Answer:

348.7 Calories (per 100 g)Step-by-step explanation:

Answer:

it is 22 because if you divide 110 ÷ 5=22

One amoeba weighs about 1.5×10^-9
grams. About how many grams would a quantity of 5×10^12 amoebas weigh?

Answers

9514 1404 393

Answer:

  7.5×10^3 grams

Step-by-step explanation:

Your calculator can tell you the product of the weight of each times the number of them. It is ...

  (1.5×10^-9)(5.0×10^12) = 7.5×10^(-9+12) = 7.5×10^3 . . . grams

About 7.5 kg.

Fill in the blanks
will choose brain

Answers

5,20,45 I sure that’s the correct answer

Select the quadrant or axis where each ordered pair is located on a coordinate plane.

Answers

Answer:

(-5,7) 2nd          (8.5,-4) 4th       (0,5) y-axis

Step-by-step explanation:

NANDARIINI RINNERIE MIRANI INDONESIA NOUTATI x2 - 7 when x = 8 mundo​

Answers

Answer: 57

Step-by-step explanation:

x² - 7

When x = 8

= x² - 7

= 8² - 7

= 64 - 7

= 57

jawabannya adalah 57


Terrell ran around a track that was 100 yards long.
How many feet did he run?

Answers

Answer:

300ft

Step-by-step explanation:

Answer:

300 ft

Step-by-step explanation:

1 yd = 3 ft

100 yd = 100 * 1 yd = 100 * 3 ft = 300 ft

Answer: 300 ft

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