In selecting a sulfur concrete for roadway construction in regions that experience heavy frost, it is important that the chosen concrete has a low value of ther- mal conductivity in order to minimize subsequent damage due to changing temperatures. Suppose two types of concrete, a graded aggregate and a no-fines aggregate, are being considered for a certain road. The table below summarizes data on thermal conductivity from an experiment carried out to compare the two types of concrete.
Ğ¢ÑÑеп ni xi si
Graded 42 0.486 0.187
No-fines Ñ 42 0.359 0.158
Assume that the conductivity for each sample of concrete is independent of that of all the others. Our interest is in determining if the mean conductivity for the graded concrete is significantly different than the mean conductivity for the no-fines concrete?
Required:
a. Formulate the above in terms of a hypothesis testing problem.
b. Give the test statistic and its reference distribution (under the null hypothesis).
c. Report the p-value of the test statistic and use it to assess the evidence that this sample provides on the scientific question of difference in mean conductivity of the two materials at the 5% level of significance.
Step-by-step explanation:
Given - In selecting a sulfur concrete for roadway construction in regions that experience heavy frost, it is important that the chosen concrete has a low value of thermal conductivity in order to minimize subsequent damage due to changing temperatures. Suppose two types of concrete, a graded aggregate and a no-fines aggregate, are being considered for a certain road. The table below summarizes data on thermal conductivity from an experiment carried out to compare the two types of concrete.
Type ni xi si
Graded 42 0.486 0.187
No-fines 42 0.359 0.158
To find - a. Formulate the above in terms of a hypothesis testing problem.
b. Give the test statistic and its reference distribution (under the null hypothesis).
c. Report the p-value of the test statistic and use it to assess the evidence that this sample provides on the scientific question of difference in mean conductivity of the two materials at the 5% level of significance.
Proof -
a.)
Hypothesis testing problem :
H0 : There is significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.
H1 : There is no significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.
b)
Test statistic :
[tex]Z = \frac{x_{1} - x_{2} }{\sqrt{\frac{s_{1} ^{2} }{n_{1}} + \frac{s_{2}^{2} }{n_{2}} } }[/tex]
[tex]Z = \frac{0.486 - 0.359 }{\sqrt{\frac{0.03496 }{42} + \frac{0.02496 }{42} } }[/tex]
[tex]Z = \frac{0.127 }{\sqrt{0.001468}}[/tex]
[tex]Z = \frac{0.127 }{0.0377}[/tex]
⇒Z(cal) = 3.3687
Z(tab) = 1.96
As Z (cal) > Z(tab)
So, we reject H0 at 5% Level of significance
p-value = 0.99962
Hence
There is significant difference in mean conductivity at the two materials.
Zane is putting the strings on 5 harps. Each harp has 48 strings.
How many strings does Zane need for all 5 harps?
Answer:
Zane needs 240 strings for 5 harps.
Step-by-step explanation:
All you have to do is multiply
48 * 5 = 240
So, the answer is 240
Hope this helps! :)
VERY EASY, WILL GIVE 50 POINTS FOR CORRECT ANSWER ASAP AND WILL GIVE BRAINLIEST.
Answer: (4,-11)
Step-by-step explanation: To perform a 180 degree rotation we switch the signs of the coordinates
Answer:
4,-11
Step-by-step explanation:
The answer is 4,-11 because if you think that you go over -4 and go up 11. Now switch the negative sign to the y coordinate because it is a 180 degree turn then you have your answer. 4,-11
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the answer to 2x+56=
Answer:
It can't be simplified or added together because one is multiplied by x and the other is not
Step-by-step explanation:
what is the mean of this data set 8,2,5,12
Answer:
6.75
Step-by-step explanation:
Add up all the numbers in the data set :
8 + 2 + 5 + 12 = 27
Divide 27 by the total numbers in the data set :
27 ÷ 4 = 6.75
Therefore, the mean if the data set is 6.75
At the pet fair, Darlene’s dog
weighed 5 times as many pounds
as Leah’s dog. Together, the dogs
weighed 60 pounds.
How many pounds does Leah’s
dog weigh?
Answer:
Darlene's dog weighs 10 pounds.
Step-by-step explanation: 5 x 10 = 50 and 50 + 10 = 60 pounds.
Hope this helps.
What is the area of the parallelogram
shown above?
[?] square feet
Answer:
299 square feet
Step-by-step explanation:
Area of a parallelogram = base × height
Base = 23 ft
Height = 13 ft
Note: the other length, 15 ft is not needed in calculating area of the parallelogram. All we need is just the length of the base and the height.
Area of the parallelogram shown = 23 × 13
Area = 299 ft²
Write the equation of the line (in point-slope form) that passes through the point (3, -4) and has a slope of 6.
Answer:
y+4=6(x-3)
Step-by-step explanation:
y-y1=m(x-x1)
y-(-4)=6(x-3)
y+4=6(x-3)
Jaime is employed by Johnson & Johnson making $30 an hour. She had $400 in sales, which
she receives an 8% commission. If she worked 20 hours last week, what was her weekly
pay?
Answer:
$632
Step-by-step explanation:
Set up an equation:
$30(20 hours) + ($400 × 0.08)
$600 + $32
$632
Solve.
b + 2/9 = 1 3/5
which angles are vertical to each other
Answer:
You need to attach the picture of the angles
Answer:
right
Step-by-step explanation: because ones left and 1 right
Which of the following is a true statement?
o & >
o = }
Os <
Answer:
the last one Denise, is the only one that is true
Step-by-step explanation:
Answer:
last one
Step-by-step explanation:
Pearl deposited $60 into her savings account. According to the rule of 72, what interest rate will cause her money to double in approximately 33 years?
Answer:2.2%
Step-by-step explanation:
Please help me.
how many observations are in this data set?
Answer:
16
Step-by-step explanation:
count the dots. each is one observation
o The day before the exam, Rebecca does a practice run. She attempts 20 glass vases and breaks 3 of them. What is her success rate, shown as a decimal?
Answer:
If the goal is to break the vases: 3/20 = 15.0% or 0.15
If the goal is to not break the vases: 17/20 = 85.0% or 0.85
How many people out of 100,000 will survive until age 90?
Answer:
81.26
Step-by-step explanation:
This amount of people survived until 90 according to an article:
20,898 + 15,034 + 26,183 + 21,196 + 15,318 + 26,479 + 15,864 + 9,952 + 21,357 = 172,281
"172,281" as a percentage is:
81.26
The percentage people out of 100,000 will survive until age 90 would be 81.26.
How to calculate unit price of something?Unit means 'single entity', the fundamental constructing block. Usually, it is 1 in mathematics and science.
Thus, unit price of something is price of 1 thing.
So, suppose we're taking about price of mangoes, then unit price will denote the price of 1 mango.
The data is given in the image attached below;
We need to find How many people out of 100,000 will survive until age 90.
A percentage is a minimum number or ratio that is measured by a fraction of 100.
The amount of people survived until 90 according to an article:
20,898 + 15,034 + 26,183 + 21,196 + 15,318 + 26,479 + 15,864 + 9,952 + 21,357
= 172,281
Therefore, "172,281" as a percentage is 81.26.
The percentage people out of 100,000 will survive until age 90 would be 81.26.
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Someone help me please!!!Divide 100 in the ratio 2:3.
Answer:
pirwvjihpwrugh
Step-by-step explanation:
wrhfuwhfuhugfrifhi
Answer:
not possible
Step-by-step explanation:
It can't be possible because the ratio would be 50:1 is possible
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Juan deposited $450 in an account that earned 7.5% simple interest.
- He did not make additional deposits and he didn't withdraw any money from the account.
What was the balance in Juan's investment account after 3 years?
Answer:
$551.25
Step-by-step explanation:
$450 x 7.5% = 33.75
33.75 x 3 = 101.25
101.25 + 450 = 551.25
PLEASE HELP ME I WILL HIVE BRAINLIST TO THE CORRECT ANSWER !!!!!!!!!!!
Answer:
I'm not 100 percent sure but I think it's the first answer choice because at 40000 3 years have passed. Hope this helps :)
Answer:
The machinery ages three years for every $10,000 loss in value.
Step-by-step explanation:
We can see from the graph that each year, the machinery loses a value of $5,000 (Goes from $50,000 to $45,000 after year one, from $45,000 to $40,000 after year two etc). So we can discount the last two answers.
If it loses $5,000 each year, it loses $15,00 after ageing three years, and $25,00 after five years. Though neither of the first two answers correspond to this, the first answer is closest.
Calculate the area of the shape below.
Answer:
24 ft²
Step-by-step explanation:
1/2x12x4=24 ft²
solve the equation f/3+22=17
Answer:
f = -15
Step-by-step explanation:
f/3 + 22 - 22 = 17 - 22
f/3 + 0 = -5
f/3 = -5
f = 3 × (-5)
f = -15
Thus, The answer is -15
-TheUnknownScientist
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Answer:
obama your mama she looks like joe mama
Which is a better deal on a $345 item: 40% off original price or 30% off and additional 15% at the register?
Answer:
345 - 40% = 207$
Step-by-step explanation:
(345 - 30%) - 15% = 205.3 (Better deal)
Answer:
30% off and additional 15% at the register
Step-by-step explanation:
Deal 1
$345 × 40% = $138
$345 - $138 = $207
Deal 2
$205.30
The manager of a restaurant recorded how many people were in different groups of
customers and how much those groups spent on food and beverages. The scatterplot below
shows the data she recorded.
Answer:
$135
Step-by-step explanation:
Answer:
D
Step-by-step explanation:
hows it goin my boi
Which graphs of ordered pairs represent functions?
Answer:
I thin its b.
Step-by-step explanation:
can anyone help me with this please! Serious plz lol
I hope this helps you
What is the answer please I need help if you send a link I will report because your just trying to scam someone
Answer:
The median is 6.
Step-by-step explanation:
answer of the question
Answer:
The number of milk chocolate pieces is between 115 and 120 pieces.
Step-by-step explanation:
A roadside assistance company gets millions of requests per year, with about a quarter of the requests in
summer and a quarter in winter. Suppose that 12% of all of the summer requests and 15% of the winter
requests are for help with a lockout. A data analyst pulls separate random samples of 200 summer and winter
requests and will look at the difference (summer winter) between the proportion of requests for help with
a lockout in each sample.
What are the mean and standard deviation of the sampling distribution of the difference in sample
proportions?
Answer: -0.03
sqrt ((0.12 (0.88) / 200) + (0.15)(0.85)/200)
Step-by-step explanation:
The mean of the sampling distribution of the difference in sample proportions is -0.03, and the standard deviation is 0.0321.
What is the standard deviation?A standard deviation (σ) is a measure of the distribution of the data in reference to the mean.
The proportion of lockout help requests in the summer population is 12% or 0.12, and the proportion in the winter population is 15% or 0.15. The sample sizes are both 200.
Using these values, we can calculate the mean and standard deviation of the sampling distribution of the difference in sample proportions:
Mean = p₁ - p₂ = 0.12 - 0.15 = -0.03
Standard deviation = √[ (p₁ (1 - p₁) / n₁) + (p₂ (1 - p₂) / n₂) ]
= √[ (0.12 (1 - 0.12) / 200) + (0.15 (1 - 0.15) / 200) ]
= √[ (0.000504) + (0.000525) ]
= √[ 0.001029 ]
= 0.0321
Therefore, the mean of the sampling distribution of the difference in sample proportions is -0.03, and the standard deviation is 0.0321.
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