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

A car travel 8km using 1 litres of petrol. How much petrol is needed to travel 152km​

Answers

Answer:

It is very interesting!

Step-by-step explanation:

So I am going to take all of this values and represent it as a proportion, So here's how it is going to look,

Km : Litre : : Km : Litre

Let's keep the missing value as x

= 8 : 1 : : 152 : x

We know that,

Product of ext. terms = Product of middle terms

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So therfore it will take 19 lites to travel 152 km.

(So to put everything in a nutshell we have to divide 8 by 152 to get the answer)

Hope this helps :)

PLZ HURRY, TIMED, WILL MARK BRAINLIEST********

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Can you show us the diagram?

If 45/60 is equivalent to 3/x, find the value of x

Answers

x = 4
EXPLANATION:

45/60 can be simplified by dividing both 45 and 60 by the same number.

We already know the numerator is 3.

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So x = 4





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Answer:

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Step-by-step explanation:

A company makes wax candles shaped like rectangular prisms. Each candle is 5 cm long, 3cm wide, and 10cm tall. If the company used 3900 cm3 of wax, how many candles did they make?

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Answer:

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Step-by-step explanation:

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Answer:

no

Step-by-step explanation:

Hello There!

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~TheMathWIz

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Answer:

hope it helps

Step-by-step explanation:

have a great day

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Answer:

I'm sorry i cant help you rn, download symbolab or math solver, I'm sure you will find your answer g

3. Marci's gross pay this month is $1,175. What is the total amount her employer will
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Answer:

it would be 266.83

Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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therefore, the answer is 4lb's.

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Answers

Answer:

10^-99

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10^-5

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Answers

Answer:

1. 26.1 cm²

Step-by-step explanation:

For area of semi circle

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= 1/2 x 3.14 x 3²

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Answers

Answer:

b. Two Sample Dependent t-test

Step-by-step explanation:

In this scenario, the best hypothesis test would be a Two Sample Dependent T-test. This is because the test would need to be seperated into two sample groups, one for the individuals that went rafting and one with the individuals that wen Kayaking. Then the data from both of these would be analyzed and compared. A dependent test would be used since the results depend on the activity in question.

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Answers

Answer:

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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Step-by-step explanation:

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Step-by-step explanation:

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Step-by-step explanation: brainilest ?

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Answers

Answer:

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Step-by-step explanation:

माना समांतर श्रेणी का प्रथम पद a और सामन्य अन्तर d है.

इसलिए..

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Answers

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Step-by-step explanation:

5×6 - 8 ÷2​

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Answer:

26

Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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Answers

Answer:

You will add!

Step-by-step explanation:

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Answer: 2

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Step-by-step explanation:

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Answers

Answer:

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Step-by-step explanation:

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Answers

Step-by-step explanation:

7=m*12

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Answers

Answer:

I think its B but im not sure

Step-by-step explanation:

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Answers

Answer:

B. 40 meters

Step-by-step explanation:

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Answers

Answer:

[tex]5 \div 6 \times 5 = 25\div 6[/tex]

25/6 is the Answer
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