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.
A new car is purchased for 22300 dollars. The value of the car depreciates at 7.5% per
year. To the nearest year, how long will it be until the value of the car is 7700 dollars?
Answer:I think 3 years
Step-by-step explanation:
sorry if im wrong
answer of the question
Answer:
The number of milk chocolate pieces is between 115 and 120 pieces.
Step-by-step explanation:
what makes 1/3 x > 12 true
Answer:
I dont know I am sorry I really had to ask a question and i don't have enough points so sorry you can report me if you want but I really need some
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
"A driving instructor is investigating whether the time a driver spends in a driverâs education course improves their score on the driverâs test. The instructor randomly selected 10 drivers from a driverâs education course and recorded the number of hours each driver attended the driverâs education course and their corresponding score on the driverâs test. Assuming all conditions for inference are met, which of the following significance tests should be used for the investigation?"
a. A chi-square test of independence
b. A two-sample t-test for a difference between means
c. A two-sample z-test for a difference between proportions
d. A linear regression t-test for slope
e. A matched pairs t-test for a mean difference
Answer:
e. A matched pairs t-test for a mean difference
Step-by-step explanation:
When the observations from two samples are paired either naturally or by design we find the differences between the two observations of each pair.Treating the differences as a random sample from a normal population with mean ud= u1-u2 and unknwn standard deviation σd we perform one sample t- test on them. This is called the paired difference t- test or a paired t- test.
Suppose 10 young recruits are given a physical training by the Army . Their weights are recorded before and after the training. These observations constitutes natural pairing .
When we eliminate the undesireable sources of variation to take observations in pairs , this is called pairing by design.
1. Find the value of x in the figure below.
74°
2x
Answer:
2x-7
Step-by-step explanation:
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:
A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 434 gram setting. It is believed that the machine is underfilling the bags. A 9 bag sample had a mean of 431 grams with a variance of 144. A level of significance of 0.01 will be used. Assume the population distribution is approximately normal. Is there sufficient evidence to support the claim that the bags are underfilled
Answer:
No, there is not sufficient evidence to support the claim that the bags are underfilled
Step-by-step explanation:
A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 434 gram setting.
This means that the null hypothesis is:
[tex]H_{0}: \mu = 434[/tex]
It is believed that the machine is underfilling the bags.
This means that the alternate hypothesis is:
[tex]H_{a}: \mu < 434[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.
434 is tested at the null hypothesis:
This means that [tex]\mu = 434[/tex]
A 9 bag sample had a mean of 431 grams with a variance of 144.
This means that [tex]X = 431, n = 9, \sigma = \sqrt{144} = 12[/tex]
Value of the test-statistic:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]z = \frac{431 - 434}{\frac{12}{\sqrt{9}}}[/tex]
[tex]z = -0.75[/tex]
P-value of the test:
The pvalue of the test is the pvalue of z = -0.75, which is 0.2266
0.2266 > 0.01, which means that there is not sufficient evidence to support the claim that the bags are underfilled.
In order to estimate the mean amount of time computer users spend on the internet each month, how many computer users must be surveyed in order to be 95% confident that your sample mean is within 11 minutes of the population mean? Assume that the standard deviation of the population of monthly time spent on the internet is 202 min. The minimum sample size required is_______computer users. (Round UP to the nearest whole number.)
Answer:
1568
Step-by-step explanation:
The computation of the minimum sample size is shown below:
Given that
Error E = 11
The population standard deviation [tex]\sigma[/tex] =217
Confidence level 1-α = 95%
Now following formula should be used
n > (Zalpha ÷ 2 × sigma ÷ E)^2
As we know that
Zalpha ÷ 2= 1.96
Now the sample size is
n> (1.96 × 202 ÷ 10)^2
= 1568
(d) State any two(2) properties of a semiconductor material.
Answer:
Semiconductors are somewhere in-between conductors and insulators. This means that they are specific when it comes to conducting electricity meaning that their conduction of electricity varies based on their condition at the time.
For instance, they can conduct electricity when heated.
Properties:
1. Perfect insulator at Absolute Zero.
As mentioned above, semi conductors are better at conducting electricity when they are heated. At Absolute zero - the lowest temperature possible - therefore, these materials would conduct absolutely no electricity thereby making them perfect insulators.
2. More resistance than Conductors but less than Insulators
As mentioned above, they have properties in-between those of insulators and conductors. One of those is their resistance. They can resist more than conductors but less than insulators.
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
Factor the expression
10x + 25
A. 2(5x + 10)
B. 5(2x + 5)
C. 10(x + 5)
D. 5(2x + 25)
Answer:
B. 5(2x+5)
Step-by-step explanation:
Factor 5 out of 10x+25. and you get 5(2x+5)
Answer:
B. 5(2x + 5
Step-by-step explanation:
If you have any questions feel free to ask in the comments
A family buys 4 airline tickets online. The family buys travel insurance that costs $19 per ticket. The total cost is $752. Let x represent the price of one ticket. Write an equation for the total cost. Then find the price of one ticket.
Answer : 169
Step-by-step explanation:
4(x+19) = 752
4x +76 = 752
4x = 752 - 76
x = 676/4
x=169
Hope this helps ;)
Please mark me the BRAINLIEST
Please help me I really need it
Answer:
Angle C
Step-by-step explanation:
By applying sine rule in the given triangle,
[tex]\frac{\text{sinB}}{CD}=\frac{\text{sinC}}{BD}=\frac{\text{sinD}}{BC}[/tex]
[tex]\frac{\text{sinB}}{\text{sinC}}=\frac{\text{CD}}{\text{BD}}[/tex]
Therefore, sides of the given triangle will be in the same ratio as the sine of the angles.
Since, BD > BC > CD
Therefore, Opposite angles of these sides will be in the same ratio.
∠C > ∠D > ∠B
Largest angle of the triangle is angle C.
a group of students collected old newspapers for a recycling project. the data shows the mass, in kilograms, of old newspapers collected by each student.
23, 35, 87, 64, 101, 90, 45, 76, 105, 60, 55
98, 122, 49, 15, 57, 75, 120, 56, 88, 45, 100.
A.) Find the range of the mass of the newspapers collected.
B.) Find the interquartile range.
Answer:
A. 107 kg
B. 49 kg
Step-by-step explanation:
Simplify.
Remove all perfect squares from inside the square root. Assume x is positive.
√ 20x^8
I can't figure this out
9514 1404 393
Answer:
143 in²
Step-by-step explanation:
The figure is dimensioned in such a way that it can be divided easily into three rectangular areas. The top rectangle is 10 in wide and 7 in high. The vertical rectangle below that is 4 in wide and 12 in high, and the square appendage on the right is 5 in square.
Then the total area is the sum of products of length and width:
A = (10 in)(7 in) + (4 in)(12 in) + (5 in)(5 in) = (70 +48 +25) in²
A = 143 in²
The area of the irregular figure is 143 in².
please help!! Area of Trapezoids and Triangles
Answer: Area of the shape is 168 ft.
Step-by-step explanation: Split the shape into 2 shapes: A rectangle and a triangle.
Area of the rectangle shape is 144 and the area of the triangle is 24. Add them and you get 168.
Give Brainliest for the correct Answer 50 points
Answer:
x-30
Step-by-step explanation:
Answer: 5(x-2)=40 5x-10 = 40 5x=50 x=10
Step-by-step explanation:
^
are these correct???
Answer:
They are all correct.
Step-by-step explanation:
1.
1/2(b)(h)
1/2(4)(6)
1/2(24)
12
2. l x w
7 x 5
35
3. (b)(h)
(8)(4)
32
2. Find the GCF of: - 4x^2 and 28x^3
Answer: 4x^2
Step-by-step explanation: Multiply that by -1 to get -4x^2 and multiply by 7x to get 28x^3
What is MEAN ABSOLUTE DEVIATION and how do you find it?
Step-by-step explanation:
Step 1: Calculate the mean. Step 2: Calculate how far away each data point is from the mean using positive distances. These are called absolute deviations. Step 3: Add those deviations together. Step 4: Divide the sum by the number of data points.
HELP ME ASAP!!!! I’m very confused and I need help!! Thanks!
Answer:
Reason 2)The transitive property of congruenceStep-by-step explanation:
There are several sort of "obvious" properties of equality/congruence. Keeping them sorted out can be a bit of a trick.
A = A . . . . reflexive property
A = B ⇔ B = A . . . . symmetric property (erroneously cited in the proof)
A = B, B = C ⇒ A = C . . . . transitive property (the one needed in the proof)
__
Not to confuse the issue, but there is also the "substitution property of equality" that says if X = Y, then X can be substituted for Y or vice versa. In the end, the transitive property is an application of this, where we're substituting for B in the second equation, or for A in the first equation.
The A=B=C form of Statement 1) in the proof is what gives you the clue it is the transitive property that is wanted here.
PLEASE HELP ASAP GEOMETRY I AM LITERALLY DYING!! 100 POINTS REAL ANSWERS ONLY OR YOU WILL BE REPORTED AND GET NO POINTS!
Let’s design a new ferris wheel!! Create a sketch of a new Ferris wheel. This new ferris wheel must have an arc length measuring 3 25π feet. What is the equation of your new ferris wheel if the center must be at least 60 feet from the ground? Be sure to show and explain all work.
9514 1404 393
Answer:
x^2 +(y -61)^2 = 625/36
Step-by-step explanation:
The graph of the above equation is attached.
If the circumference of the wheel is 25π/3 feet, the diameter is ...
d = C/π = (25/3π)/π = 25/3 . . . feet, about 8.33 feet
The radius will be half that value, or 25/6 feet.
For a center point (h, k) and radius r, the equation of a circle is ...
(x -h)^2 +(y -k)^2 = r^2
You want the center to be more than 60 feet from the ground, so we can make it be 61 feet. The horizontal location is not specified, so we can make it zero.
This means we apparently want the equation for a circle of radius 25/6 feet with a center that is (x, y) = (0, 61). The equation of this circle is ...
x^2 +(y -61)^2 = 625/36
Directions: Tables, graphs (use grid points!), and stories are provided. For each case:
1. Find the slope
2. Find the y-intercept
3. Write an equation
4. Explain how you know the slope and y-intercept are correct. Check 2 points in your equation to show it is correct.
Linear Function Representation- Equation - Slope - Intercept
x y
0 4
2 9
4 14
6 19
8 24
Answer:
See explanations below
Step-by-step explanation:
Using the coordinate points in the table (0, 4) and (2, 9)
Slope m = y2-y1/x2-x1
m = 9-4/2-0
m = 5/2
slope = 5/2
Get the y-intercept
Substitute m = 5/2 and (0,4) into y = mx+c
4 = 5/2(0) + c
4 = 0+c
c = 4
y-intercept is 4
Get the equation
Recall that y = mx+c
y = 5/2x + 4
Using another 2 points (2,9) and (4, 14)
Slope = 14-9/4-2
Slope = 5/2
Since the slope is the same for the coordinates, hence the the equation is correct
I need help on number 26
Answer:
The number of required shelves is 5
You have to find the HCF of 45, 105, and 75.
Find the value of x in the parallelogram below.
Answer:
B) x = 12
Step-by-step explanation:
m∡EOU = m∡TQE
m∡EOU =180 - (39+45) = 96°
m∡TQE: 7x + 12 = 96
7x = 84
x = 12
Help please!!
Brainliest if right
Answer:
top and bottom
Step-by-step explanation:
Translate this sentence into an equation.
54 is the sum of 15 and Jenny's age.
Use the variable j to represent Jenny's age.
Answer:
54= 15 + J
Step-by-step explanation:
j= 39
Plz help me the question is in the picture
