The concentration of hexane (a common solvent) was measured in units of micrograms per liter for a simple random sample of sixteen specimens of untreated ground water taken near a municipal landfill. The sample mean was 228.0 with a sample standard deviation of 4.3. Twenty specimens of treated ground water had an average hexane concentration of 224.6 with a standard deviation of 5.0. It is reasonable to assume that both samples come from populations that are approximately normal.
Can you conclude that the mean hexane concentration is less in treated water than in untreated water? Use the ? = 0.10 level of significance.
No
Yes

Answers

Answer 1

Answer:

Yes, it can be concluded that the mean hexane concentration is less in treated water than in unsaturated water

Step-by-step explanation:

The number of of specimen in the samples of untreated water, n₁ = 16

The sample mean, [tex]\overline x_1[/tex] = 228.0

The sample standard deviation, s₁ = 4.3

The number of of specimen in the samples of treated water, n₂ = 20

The sample mean, [tex]\overline x_2[/tex] = 224.6

The sample standard deviation, s₂ = 5.0

The level of significance = 0.10

The null hypothesis, H₀; [tex]\overline x_1[/tex] ≥ [tex]\overline x_2[/tex]

The alternative hypothesis, Hₐ;  [tex]\overline x_1[/tex] < [tex]\overline x_2[/tex]

The degrees of freedom = 16 - 1 = 15

The test statistic, [tex]t_{\alpha}[/tex] = 1.341

[tex]t=\dfrac{(\bar{x}_{1}-\bar{x}_{2})}{\sqrt{\dfrac{s_{1}^{2} }{n_{1}}-\dfrac{s _{2}^{2}}{n_{2}}}}[/tex]

Plugging in the values, we get;

[tex]t=\dfrac{(224.6- 228.0)}{\sqrt{\dfrac{5.0^{2}}{20} -\dfrac{4.3^{2} }{16}}} \approx -11.0675[/tex]

Given that the t-value is large, the corresponding p-value is low, therefore, we fail to reject the null hypothesis and there is considerable statistical evidence to suggest that the mean hexane concentration is less in treated than in untreated water, therefore, we have; [tex]\overline x_1[/tex] ≥ [tex]\overline x_2[/tex]


Related Questions

PLEASE ANSWER ASAP FOR BRAINLEST!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Answers

Answer:

bottom half

bottom- 3 x 12.5 = 37.5

front side- 3 x 4 = 12

back side- 12

left side- 4 x 12.5 = 50

right side- 50

total: 161.5

top half

front triangle- (3x4)/2 = 6

back triangle- 6

left side- 4 x 12.5 = 50

right side- 50

total: 112

161.5 + 112 = 273.5

find the value of x. round to the nearest degree.

Answers

Answer:

What you should do in this case is to use the following trinonometric relationship:

senx = C.O / h

Where

C.O: Opposite leg.

h: hypotenuse.

Substituting:

senx = (7) / (9)

Clearing x:

x = ASIN ((7) / (9))

x = 51.05755873

Answer:

The value of x is

x = 51 degrees.

Step-by-step explanation:

What number divided by 4 equals 6?
Type the correct answer, then press Enter.

Answers

Answer:

24

Step-by-step explanation:

Let x be the number.

[tex]x/4=6[/tex]

Multiply both sides by 4 to isolate x

[tex](x/4)4=6*4\\x=24[/tex]

I hope this helps!

Identify the correct form of the following geometric sequence.

5 , 35 , 245 , 1,715 , ...

Answers

The correct form of the geometric sequence is:[tex]5, 35, 245, 1,715, ... = 5, 5 * 7, 5 * 7^2, 5 * 7^3, ...[/tex]

how to Identify the correct form of the geometric sequence.

To identify the correct form of the geometric sequence 5, 35, 245, 1,715, ..., we can look for a common ratio between consecutive terms.

To find the common ratio, we divide any term by its preceding term. Let's take the second and first terms:

35 / 5 = 7

Now, let's check the third and second terms:

245 / 35 = 7

Similarly, for the fourth and third terms:

1,715 / 245 = 7

Since we obtained the same result (7) for all ratios, we can conclude that the common ratio of this geometric sequence is 7.

Now, let's express the general form of the sequence using the first term (a) and the common ratio (r):

a, ar, [tex]ar^2,[/tex] [tex]ar^3,[/tex] ...

Substituting the given values:

a = 5 (the first term)

r = 7 (the common ratio)

The correct form of the geometric sequence is:

[tex]5, 5 * 7, 5 * 7^2, 5 * 7^3[/tex], ...

Simplifying the terms, we get:

5, 35, 245, 1,715, ...

Therefore, the correct form of the geometric sequence is:

5, 35, 245, 1,715, ... = 5, 5 * 7, 5 * 7^2, 5 * 7^3, ...

Learn more about geometric sequence at https://brainly.com/question/1509142

#SPJ1

the 30% discount on a $49 dollhouse​

Answers

Answer:

34.30

Step-by-step explanation:

$14.70 is 30% of $49 so

The total would be $34.30 after the discount

But the discount is %14.70

HELP!!!!! WILL GIVE BRANLIEST !!!!!

Answers

Answer:

F = (-2,4); E = (-2,0); D = (2,0)

Step-by-step explanation:

F = 4 points from A, so by a scale factor of 2, it would be 2 times father away from A. The same thing applies for all of the other points; just find how much father A is from a point, then dilate that point by multiplying it by the scale factor, and settling the point closer or father from A.

Quadrilateral A'B'C'D' Is the image of quadrilateral ABCD under a dilation.

What is the scale factor of the dilation?

Answers

Answer:

Scale factor = [tex]\frac{1}{4}[/tex]

Step-by-step explanation:

Formula for the dilation to be used,

Scale factor = [tex]\frac{\text{Dimension of the image}}{\text{Dimension of the original}}[/tex]

                    = [tex]\frac{A'B'}{AB}[/tex]

                    = [tex]\frac{1}{4}[/tex]

Therefore, scale factor by which quadrilateral ABCD has been dilated to form image quadrilateral A'B'C'D' is [tex]\frac{1}{4}[/tex].

Find the perimeter of the figure to the nearest hundredth. due today

Answers

*☆*――*☆*――*☆*――*☆*――*☆*――*☆*――*☆*――*☆**☆*――*☆*――*☆*――*☆

Answer: 36.57

Explanation:

6x4 = 24

3.14(2)^2 = 12.56

12.57+24=36.57

I hope this helped!

<!> Brainliest is appreciated! <!>

- Zack Slocum

*☆*――*☆*――*☆*――*☆*――*☆*――*☆*――*☆*――*☆**☆*――*☆*――*☆*――*☆

The difference of two numbers is 14.Twice the smaller is 6 more than the larger.Find the numbers.

Answers

the numbers are 6 2/3 and 7 1/3

Simplify:
Camilla goes to the super market and buys two apples. each apple is $1.75. Camilla has $5.00 left. write an expression to represents this problem. Don't forget to use a variable!

Answers

Answer:

[tex] \huge \boxed{ \boxed{t - 3.5 = 5}}[/tex]

Step-by-step explanation:

to understand thisyou need to know about:equationlet's solve:

a apple costs 1.75

2 apple costs 1.75×2=3.5

let her total money be t

according to the question

t-3.5=5

Please solve the following. Solve for X. PLEASE HELP

Answers

Answer:

8

Step-by-step explanation:

(x+4)/x=24/16

24x=16x+64

8x=64

x=8

lol plss we did this literally a week ago and I forgot how to do it

Answers

Answer:

okay so i believe its area (if its not ill comment the right answer) so you just do the height (12) times the length (12) giving you 144

Step-by-step explanation:

If the scale factor of Figure A to Figure B is 7:2 find the perimeter of Figure A.

Answers

Could you attach the photo

15% of 20 is ??? please helpp

Answers

Answer:

I believe it is 3

Step-by-step explanation:

Answer:

the answer is 3 brainlest plz

Step-by-step explanation:

A pizza pan is removed at 9:00 PM from an oven whose temperature is fixed at 450°F into a room that is a constant 70°F. After 5​ minutes, the pizza pan is at 300°F.
​(a) At what time is the temperature of the pan 125°F? ​
(b) Determine the time that needs to elapse before the pan is 150°. ​
(c) What do you notice about the temperature as time​ passes?

Answers

Answer:

A) It will get to a temperature of 125°F at 9:19 PM

B) It will get to a temperature of 150°F at 9:16 PM

C) as time passes temperature approaches the initial temperature of 450°F

Step-by-step explanation:

We are given;

Initial temperature; T_i = 450°F

Room temperature; T_r = 70°F

From Newton's law of cooling, temperature after time (t) is given as;

T(t) = T_r + (T_i - T_r)e^(-kt)

Where k is cooling rate and t is time after the initial temperature.

Now, we are told that After 5​ minutes, the temperature is 300°F.

Thus;

300 = 70 + (450 - 70)e^(-5k)

300 - 70 = 380e^(-5k)

230/380 = e^(-5k)

e^(-5k) = 0.6053

-5k = In 0.6053

-5k = -0.502

k = 0.502/5

k = 0.1004 /min

A) Thus, at temperature of 125°F, we can find the time from;

125 = 70 + (450 - 70)e^(-0.1004t)

125 - 70 = 380e^(-0.1004t)

55/380 = e^(-0.1004t)

In (55/380) = -0.1004t

-0.1004t = -1.9328

t = 1.9328/0.1018

t ≈ 19 minutes

Thus, it will get to a temperature of 125°F at 9:19 PM

B) Thus, at temperature of 150°F, we can find the time from;

150 = 70 + (450 - 70)e^(-0.1004t)

150 - 70 = 380e^(-0.1004t)

80/380 = e^(-0.1004t)

In (80/380) = -0.1004t

-0.1004t = -1.5581

t = 1.5581/0.1004

t ≈ 16 minutes.

Thus, it will get to a temperature of 150°F at 9:16 PM

C) As time passes which means as it approaches to infinity, it means that e^(-kt) gets to 1.

Thus,we have;

T(t) = T_r + (T_i - T_r)

T_r will cancel out to give;

T(t) = T_i

Thus, as time passes temperature approaches the initial temperature of 450°F

Choose all answers that apply

a. 7°
b. 45°
c. 90°
d. 210°
e. 355°
f. none of the above

Answers

Answer:

a,b,c,d and e

Step-by-step explanation:

a circle can be rotated any degree an be symmetrical therefore it has a infinite order of rotational symmetry

thus meaning that the answers are a , b , c, d and e

The tape diagram represents an equation.
W
1.3
2.7
Write an
equation to represent the image.

Answers

Answer:

w+1.3=2.7

Step-by-step explanation:

Answer:

1.3 + w = 2.7

Step-by-step explanation:

Hope this helps

What is the equation of the line that passes through the point (-4,-8)(−4,−8) and has a slope of 44?

Answers

Answer:

y = 44x + 184

Step-by-step explanation:

y = mx + b

-8 = 44(-4) +b

-8 = -176 + b

176 + 8 = b

184 = b



What is the probability that a randomly selected graduate has a job if he or she is attending college? Give your answer as

a decimal precise to two decimal places.

P=

What is the probability that a randomly selected graduate attends college if he or she has a job? Give your answer as a

decimal precise to two decimal places.

P-

Answers

Complete question :

Suppose that of the 300 seniors who graduated from Schwarzchild High School last spring, some have jobs, some are attending college, and some are doing both. The following Venn diagram shows the number of graduates in each category. What is the probability that a randomly selected graduate has a job if he or she is attending college? Give your answer as a decimal precise to two decimal places.

What is the probability that a randomly selected graduate attends college if he or she has a job? Give your answer as a decimal precise to two decimal places.

Answer:

0.56 ; 0.60

Step-by-step explanation:

From The attached Venn diagram :

C = attend college ; J = has a job

P(C) = (35+45)/300 = 80/300 = 8/30

P(J) = (30+45)/300 = 75/300 = 0.25

P(C n J) = 45 /300 = 0.15

1.)

P(J | C) = P(C n J) / P(C)

P(J | C) = 0.15 / (8/30)

P(J | C) = 0.5625 = 0.56

2.)

P(C | J) = P(C n J) / P(J)

P(C | J) = 0.15 / (0.25)

P(C | J) = 0.6 = 0.60

given triangle ABC if angleA=25degrees, angle B=75degrees and a=14 what is the length of side b to the nearest whole number

Answers

9514 1404 393

Answer:

  b = 32

Step-by-step explanation:

The law of sines tells you ...

  b = a·sin(B)/sin(A)

  b = 14·sin(75°)/sin(25°) ≈ 31.998

  b ≈ 32 . . . . units

The remaining questions refer to the following situation: Suppose a certain farmer wants to find out if the average length of the green beans in her field is 4 inches. She collects a random sample of 100 beans and get a sample mean of 3.75 inches. (Suppose she knows that the population standard deviation of bean length is 0.5.) What is the population in this situation

Answers

Answer:

The population in this situation is all green beans in her field.

Step-by-step explanation:

Informally, if you take a sample of an object, the population in all of these objects.

In this question:

Sample of 100 green beans in her field. This means that the population in this situation is all green beans in her field.

Could someone help me with with 6-10??

Answers

Answer:

You need a protractor

Step-by-step explanation:

to measure the angles

CAN SOMEONE HELP ME!!

Rich needs $50,000 for a down payment on a home in 5 years. How much must he deposit into an account that pays 6% interest, com pounded quarterly , in order to meet his goal ?

Answers

Answer

37 ,123.52

Explanation

the image above, hope it helps

carl has 1,064 legos. sharon has 19 time the amount of legos. how many legos does sharon have

Answers

1064 x

19

________

20216 legos

Sharon has 20216 legos

a pet shop sells a 6 can multipack of dog food for £3.18 and a 15 can multipack for £7.80. which multipack is the best value for money​

Answers

Answer:

the 15 multi pack

Step-by-step explanation:

It is the 15 can multipack, when you divide the cans by the price it gives you the price of one can and the 15 can multipack, one of the cans have a lower price than one of the cans from the 6 can multipack

Impossible Not Ukely Equslly Ukely & Unlikely Ukoly Certain Events: a. You will win the grand prize in a raffle if you purchased 2 of the 100 tickets. b. You will wait less than 10 minutes before ordering at a fast-food restaurant. c. You will get an even number when you roll a standard number cube. d. A four-year-old child is over six feet tall. e. No one in your class will be late to class next week. f. The next baby born at a hospital will be a boy, g. It will snow at our school on July 1. h. The sun will set today before 11:00 p.m. i. Spinning the spinner shown will result in green. j. Spinning the spinner shown will result in yellow.​

Answers

Answer:

a. Unikely

b. Likely

c. Equally likely

d. Unlikely

e. Equally likely

f. Equally likely

g. Unlikely

h. Likely

i. No SPINNER SHOWN?

j. NO SPINNER SHOWN?

Step-by-step explanation:

Danny reads for one half hour every day.
At the end of four weeks, how many hours has Danny read?

Answers

There are 7 days in a week.

1/2 hour x 7 days = 3 1/2 hours per week.

3 1/2 hours per week x 4 weeks = 14 hours

He read for a total of 14 hours

Answer:

14 hours

Step-by-step explanation:

half hour = 30 minutes

1 week = 7 days

30(minutes) x 7(days) = 210 minutes

210(minutes) x 4(weeks) = 840 minutes

Now we know how much time Danny has read (840 minutes), but we need to know what that is in hours.

840 minutes = how long Danny has read in minutes

60 minutes = hour

840(minutes) ÷ 60(minutes) = 14(hours)

Please help

Look at picture

Answers

Answer:

J = 2

Step-by-step explanation:

Volume formula: V = whl (width)(hight)(lenght)

solve for J (width)

Rearrange the formula:

w = V/lh

60/5 x 6 = 2

the value is 2 meters. to know that use the formula v/hl

(1.75)^2 in expanded form

Answers

Answer:

1.75 x 1.75

fillerfillerfiller

Can someone tell me this one?

Answers

j = 35 + 10 since 35 is 10 less than j just add 10 to 35 to get j :^)

Answer:

The answer is 45

Step-by-step explanation:

35+10=45

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