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 help with this.

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Answer:

A and C are the correct options.

Is my answer choice wrong or right?

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Answer:

It is correct

Step-by-step explanation:

Gr8 job

Which choice is equivalent to the product below?

Answers

Answer:

equivalent of √6 . ✓3 is option a. 3√2

√6×3 = √18 = √9. √2 = 3√2

Jim did 35 push-ups on Saturday, 42 push-ups on Sunday, 49 push-ups on Monday, and 56 push-ups on Tuesday. What kind of sequence is this?

Answers

Answer:

increasing sequence of +7

Step-by-step explanation:

please mark brainiest

please give 5 stars

thank you

Identify the distance between points (−1,7,10) and (6,−3,2), and identify the midpoint of the segment for which these are the endpoints. Round to the nearest tenth, if necessary.

Answers

Answer:

d ≈ 14.6 units; M (2.5, 2, 6)

Step-by-step explanation:

Using the distance formula for 3-D dimensions, you get the √(213) which equals 14.6

Then, using the midpoint formula for 3-D dimensions, you find the coordinates 2.5 for x, 2 for y, and 6 for z.

Find the area of the polygon 2cm 2cm 3cm in square centimeters​

Answers

Answer:

12sq cm

Step-by-step explanation:

For Area, we do lenth x width x height. Here, the lenth and the width is 2, so we do 2x2 which is 4. Next the height is 3 so we do 4x3 which is 12. There is your answer. Hope it helps!


Use the figure to find the Volume.

Answers

Answer:

12π un^3

Step-by-step explanation:

Use the fomula: V= πr2 h

The radius is 2 and the height is 3.

I really don't know how to explain this but I can try, with a self- explanatory steps including the formula .

The work is in the screen shot goodluck.

Hope this helped!

Stay Safe!

EFGH is translated 3 units to the left and 7 units up.
у
1
-1
1 2
4
5
6 7 8 x
E4,-1)
H(
6-2)
2 F10,-3)
-3
G(2, 4)
-5
6
-7
What are the coordinates of H'?

Answers

Answer:

B: 3, 5

Step-by-step explanation:

Lol, literally just took the test on Ap3x right now

Final question - whats the answer?

Answers

Answer: 7^5 or 7 to the fifth power.

Step-by-step explanation: This is an exponent meaning you count the 7’s and in the first picture there’s 5 7’s. This means that the number your putting to a power is the yellow box so that’s 7 and the exponent is 5 not 4 because if you did 7 to the first power it’s still 7 so it would be 7 to the 5th power or 7^5

im confused isn't there supposed to be three numbers ​

Answers

Answer:

m<S=63°

Step-by-step explanation:

The angle formed with the radius and a tangent is 90 degrees. (<T)

180-90-27=63

Jean worked 47 hours last week and was paid $527. How much was she paid per hour?

Answers

Answer:

11.2127659574

Step-by-step explanation:

Answer:

$11.21 per hour.

Step-by-step explanation:

Divide the pay by the hours worked and round to the nearest tenth.

527/ 47 = 11.21276596 then round to 11.21

Simplify.

Please help!!

Answers

Answer:

m√n+2n-n√m

Step-by-step explanation:

4√n^2+√m^2n-√4n^2-√mn^2

m√n+2n-n√m

The Arc Electronic Company had an income of 59 million dollars last year. Suppose the mean income of firms in the same industry as Arc for a year is 45 million dollars with a standard deviation of 7 million dollars. If incomes for this industry are distributed normally, what is the probability that a randomly selected firm will earn more than Arc did last year

Answers

Answer:

0.0228 = 2.28% probability that a randomly selected firm will earn more than Arc did last year

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Suppose the mean income of firms in the same industry as Arc for a year is 45 million dollars with a standard deviation of 7 million dollars

This means that [tex]\mu = 45, \sigma = 7[/tex]

What is the probability that a randomly selected firm will earn more than Arc did last year?

Arc earned 59 million, so this is 1 subtracted by the pvalue of Z when X = 59.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{59 - 45}{7}[/tex]

[tex]Z = 2[/tex]

[tex]Z = 2[/tex] has a pvalue of 0.9772

1 - 0.9772 = 0.0228

0.0228 = 2.28% probability that a randomly selected firm will earn more than Arc did last year

If you know how to do this please help me.

Answers

Answer:

Undefined or no values (assuming no negative zero)

Step-by-step explanation:

The absolute value of a number (a) keeps/turns it positive. A positive number can never be equal to a negative number.

Solve | 2x | = | x + 3 | by graphing

Answers

Answer:the answer is 3 and -1

Step-by-step explanation:

X=3

And

X=-1

TIMED TEST WILL GIVE BRAINLIEST

Answers

Answer: 12?

Step-by-step explanation:

Answer: 12
Explanation: 2piR = circumference so to find just radius take out 2pi so you would do 24pi/2pi and cancel out the pi and simplify the 24/2 to just 12 :)

If you answer I’ll reward brainiest it’s easy

Answers

Answer:

1/9 of the total bag is chocolate

A quantity who values do not change is called a

A) Variable
B) Pattern
C) Constant
D) Algebraic expression

Answers

Answer:

C)  constant

Step-by-step explanation:

it would be a constant ! you can remember this by thinking of the meaning of the word constant; consistent. it does not change, constantly. i hope that helped some :)

Daniel has 250 songs on his MP3 player.
Ninety-five of the songs are by the same singer.
What percent of Daniel's songs are by that one
singer??
A. 26%
B. 38%
C. 62%
D. 83%

Answers

Its B which is 38%..............

does y = -5x represent a proportional relationship?

Answers

Answer: No

Step-by-step explanation: A proportional relationship can be described by an equation of the form y = kx, where k is a number called the constant of proportionality.

A- (x+4) (4x-1)
B- (x-4)(4x-1)
C-(x+4)(4x+1)
D-(x-4)(4x+1)

Answers

D-(x-4)(4x+1) is your answer

Answer:

4x²-15x-4

doing middle term factorization

4x²-16x+x-4

4x(x-4)+1(x-4)

(x-4)(4x+1)

a train leaves a station at 18:20 and arrives its destination at 02:28.How long did it take?​

Answers

Answer:

8 hours and 8 minutes

Step-by-step explanation:

there are 24 hours on the clock so if you add 6 to the 24 it would make you be at 0:00 so then you would add 2 hours and since 28 is 8 more than 20 it would be 8 hours and 8 minutes.

Question 11
2 pts
If the temperature at 10:00 am is -23° F and two
hours later at 12.00 pm the temperature rose 6
degrees Fahrenheit, what is the
temperature at
12:00 pm in degrees?

Answers

-17°F bc -23+6 is -17

PLZ HELP
What is the x-intercept of the graph y = 2x - 14?

-14
-7
0
7

Answers

To find -intercept/zero, substitute 0=2x-14 Move the variable to the left-hand side and change its sign -2x=-14 Divide both sides of the equation by x=7
y=2x-14

substitute y=0
0=2x-14
-2x=-14
x=-14/-2
x=7

HELP PLS MIGHT GIVE BRAINLIST BUT ONLY IF 2 PEOPLE ANSWER!

Answers

the answer to the question is b.
yes the answer is B indeed

15=5x+45

What is the value of x?

Answers

15 = 5x + 45

15 - 45 = 5x

-30 = 5x

-30/5 = x

-6 = x

Answer:

x= -6

Step-by-step explanation:

15=5x+45

15-45=5x

-30=5x

-30/5=5x/5

-6=x

x= -6

Kennedy lives in the middle of the city. Her friend Zoe lives 8 miles to the west and her friend Shiloh lives 6 miles to the south. Approximately how far apart do Zoe and Shiloh live from each other?

Answers

Answer:

i would say about 16 miles.

Answer:

Step-by-step explanation:

Draw a picture. The lines between their houses forms a right triangle. Kennedy is at the 90°. The distance between Shiloh and Zoe is the hypotenuse of the triangle, so use the Pythagorean Theorem.

Distance² = 8² + 6² = 100

Distance = √100 = 10 miles

I will mark you brainalist

Answers

Answer:

the answer is X=-7

,,,,,

Answer:

it would be x=7

Step-by-step explanation:

brainliest pls

if a ferris wheel at the fair has a radius of 18 ft how far will you travel after 8 trips around the ferris wheel

Answers

The answer is 113.1 (rounded) 113.097 (not rounded)

The formula is 2 π r

1
Pierre and Jen collect badges. Pierre has 3 times as many badges as Je
This can be shown by p= 3j, where p = the number of badges
Pierre owns and j = the number of badges Jen owns.
If Pierre has 12 badges, how many does Jen have?​

Answers

Pierre and Jen collect badges. Pierre has 3 times as many badges as Je

This can be shown by p= 3j, where p = the number

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