Help me fast I need it please

A sample size of 32 is necessary if the width of the 95% interval is to be 0.38.

To compute the confidence intervals (CI) for the true average porosity of coal seams, we can use the t-distribution since the sample sizes are relatively small (less than 30) and the true standard deviation is unknown. The formula for the confidence interval is:

CI = sample mean ± t_critical * (sample standard deviation / √(sample size))

where t_critical is the critical value of the t-distribution for the desired confidence level and degrees of freedom (sample size - 1).

(a) For the 95% CI of the true average porosity of the first seam with a sample mean of 4.85 and a sample size of 19, the t_critical value for a 95% confidence level with 18 degrees of freedom is approximately 2.101 (you can find this value from t-distribution tables or using a calculator/software). The sample standard deviation is not the true standard deviation, so we use the sample standard deviation instead, which is 0.71.

CI (95%) = 4.85 ± 2.101 * (0.71 / √19)

CI (95%) ≈ 4.85 ± 0.296

So, the 95% confidence interval for the true average porosity of the first seam is approximately (4.554, 5.146).

(b) For the 98% CI of the true average porosity of the second seam with a sample mean of 4.56 and a sample size of 13, the t_critical value for a 98% confidence level with 12 degrees of freedom is approximately 2.681.

CI (98%) = 4.56 ± 2.681 * (0.71 / √13)

CI (98%) ≈ 4.56 ± 0.365

The 98% confidence interval for the true average porosity of the second seam is approximately (4.195, 4.925).

(c) To find the necessary sample size for a 95% confidence level and a CI width of 0.38, we rearrange the CI formula:

Sample size = [(t_critical * sample standard deviation) / (CI width / 2)]^2

Given t_critical for a 95% confidence level and a sample standard deviation of 0.71:

Sample size = [(1.96 * 0.71) / (0.38 / 2)]^2 ≈ 31.52

Since the sample size must be a whole number, we round up to 32. Therefore, a sample size of 32 is necessary to achieve a 95% confidence interval with a width of 0.38.

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Harper would have $8,817 in her account.

To find out how much money Harper would have in her account when Alyssa's money has tripled in value.

We need to calculate the future value of Alyssa's investment and then find the corresponding value for Harper's investment.

The formula for calculating the future value with compound interest is:

Future Value = Principal * (1 + \((interest \hspace{1mm} rate / number of \hspace{1mm} compounding \hspace{1mm} periods))^{(number \hspace{1mm} of compounding \hspace{1mm} periods \times time)}\)

In this case, Alyssa's principal is $5,700, the interest rate is 5 1/4% (or 5.25% as a decimal), and the compounding is daily.

The time it takes for Alyssa's investment to triple in value is not given, so we'll need to determine it.

Let's assume it takes t years for Alyssa's investment to triple. We can use the formula for compound interest to find the value of t:

$\(5,700 * (1 + 0.0525/365)^{(365t)}\) = $5,700 * 3

Simplifying the equation, we have:

\((1 + 0.0525/365)^{(365t)} = 3\)

Take the natural logarithm of both sides:

\(ln[(1 + 0.0525/365)^{(365t)}] = ln(3)\)

365t * ln(1 + 0.0525/365) = ln(3)

Solve for t:

t = ln(3) / (365 * ln(1 + 0.0525/365))

Using a calculator, we find that t is approximately 7.587 years.

Now we can calculate the future value of Alyssa's investment:

Future Value of Alyssa's Investment = $\(5,700 * (1 + 0.0525/365)^{(365 * 7.587)}\)

To find out how much money Harper would have in her account when Alyssa's money has tripled, we need to calculate the future value of Harper's investment with continuous compounding.

The formula for continuous compound interest is:

Future Value = \(Principal * e^{(interest rate\hspace {1mm} \times time)}\)

In this case, Harper's principal is also $5,700, and the interest rate is 5 3/4% (or 5.75% as a decimal). The time will be the same as it took for Alyssa's investment to triple, which is approximately 7.587 years.

Future Value of Harper's Investment =\($5,700 * e^(0.0575 * 7.587)\)

Using a calculator, we can calculate the approximate future value of Harper's investment.

Calculating the expression $\(5,700 * e^{(0.0575 * 7.587)},\) we get:

$\(5,700 * e^{(0.4372375)}\) ≈ $5,700 * 1.548366 ≈ $8,817

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Answer:

B. ΔDEF ≅ ΔSRU

Step-by-step explanation:

Hope this helps!

The congruence statement is \(\triangle D EF \cong \triangle SRU\)

The pre-image of the triangle is triangle DEF.

When reflected over the y-axis, and then translated down 4 units and right 3 units, the image of the triangle is SRU

Translation and reflection are rigid transformations.

Hence, the congruence statement is \(\triangle D EF \cong \triangle SRU\)

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Answer:

See below for answers

Step-by-step explanation:

y=5(2)ˣ

y=5(2)⁻²=5(1/2²)=5(1/4)=5/4

y=5(2)⁻¹=5(1/2¹)=5(1/2)=5/2

y=5(2)⁰=5(1)=5

y=5(2)¹=5(2)=10

y=5(2)²=5(4)=20

Answer:

5/4

5/4 = 1 1/4

It does not belong here

Step-by-step explanation:

Answer:

5/4 because the top is bigger than the bottom

The transitive closure by arithmetic operations on the adjacency matrix is  Compute A⁰ + A¹ + ... + A⁽ⁿ⁻¹⁾ where + is standard addition (integers)

The transitive closure of a graph is the set of all possible paths from one vertex to another in the graph.

The best method to determine the transitive closure by arithmetic operations on the adjacency matrix is C.

Compute

=> A⁰ + A¹ + ... + A⁽ⁿ⁻¹⁾

where + is standard addition (integers).

The standard addition of integers is used because we are counting the number of paths between each vertex.

In this method, we start by computing A⁰, which is simply the adjacency matrix itself.

A¹ gives us the number of paths between each vertex that are one step long. A² gives us the number of paths between each vertex that are two steps long, and so on. We continue this process until we have computed

=> A⁽ⁿ⁻¹⁾

where n is the number of vertices in the graph.

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Let x= the average for all three classes combined. So x=85.25.

When you add two or more numbers and divide the result by the number of numbers you added together, you obtain an average.

The arithmetic mean is determined by adding a collection of numbers, dividing by their count, and obtaining the result.

average  =  total points / number of students

total points = average*number of students

Let the total number of students in  each class = a , b  and x

The total number of points the first class amassed  was   80a

The total number of points amassed by the second class was  85b

The total number of points amassed by the third class = 89c

For the first two classes we have

[ 80a + 85b ] / [ a + b] = 83

80a + 85b = 83a + 83b  

subtract  80a, 83b from both sides    

3a = 2b

a = 2/3b

For the second two classes we have

[ 85b + 89c ]  / [ b + c ]  =  87  

[  85b + 89c ]  = 87 [b + c]

85b + 89c = 87b + 87c      

subtract  85b, 87c from both sides

2c = 2b  

b  = c

For the three classes.....

Total points by all three classes /  number of class members  = the average for all three classes

[ 80a + 85b  + 89c ] /  [ a + b + c ]   =[sub for  a and c ]  

[80 (2/3)b  + 85b  + 89b]  /  [ (2/3)b  + b  + b ]  

b [ 80 (2/3)  + 85  + 89 ]  / [  b [( 2/3) + 1 + 1] ]       [cancel the b's ]

[ 80 (2/3) + 85 + 89]  [  8/3 ]

[ 160/3 + 85 + 89 ] /  [8/3] =

[ 160/3  + 255/3 + 267/3]  / [8/3]     multiply  top/bottom by 3

[160 + 255 + 267 ] / 8  =  

85.25  = average for all three classes

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Answer:

y=60

Step-by-step explanation:

\(15=\frac{y}{-4} \\(15)*-4=(\frac{y}{-4} )*-4\\-240=y\)

To determine the equation for a trend line that models the relationship between time and Kim's annual salary, we need to analyze the given data in the table. However, since you have not provided the table or the values for Kim's earnings, I cannot calculate the specific equation.

Nevertheless, assuming we have a table with the years from 1996 to 2004 and Kim's corresponding annual salaries, we can use regression analysis or the method of least squares to find the best-fitting line. This line represents the approximate relationship between time and Kim's annual salary.By setting 1996 as the starting point (time = 0), we can use the other years as the x-values and Kim's annual salaries as the y-values. With the data points, we can calculate the slope and intercept of the trend line using statistical techniques. The resulting equation of the trend line will be in the form y = mx + b, where y represents Kim's annual salary.

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Answer:

A. y=2x-9

Step-by-step explanation:

A. Parallel lines have the same slope. That means the line y=2x+3 has the same slope as any line parallel to it. So the slope is 2.

Using m=2, substitute it and (4,-1) into the point slope form and simplify to find the y-intercept.

the answer is 165 I think because I didn't understand the question

The nature of the roots of 2x² 3x 5 0 are imaginary, as it is not possible to solve for real numbers.

To solve this equation, we first factor out the coefficients (2 and 5). Factoring out 2 gives us x² + 1.5x + 5 = 0. After that, we solve for x using the quadratic formula:

x

= -1.5 ± √(-1.5² - 4(1)(5)) / 2(1). This is reduced to x = -1.5 9.5 / 2, an imaginary number that cannot be solved using real values. This indicates that the equation's roots are fictitious.

x

= -1.5 ± √(-1.5² - 4(1)(5)) / 2(1)

x = -1.5 ± √9.5 / 2

x = -1.5 ± √(9.5)i / 2

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Answer:

well when time is zero, meaning no movement has been done because there is no speed, is the starting point of the bee, so the answer is C

Step-by-step explanation:

Answer:

its 10.5 cm

Step-by-step explanation:

its what I got off of khan

The base area of the oblique triangular prism is 10.5 square cm

The volume is given as:

Volume = 63 cubic cm

The height of the prism is:

Height = 6 cm

The base area of the prism is then calculated using:

Area = Volume/Height

So, we have:

Area = 63/6

Evaluate

Area = 10.5

Hence, the base area of the triangular prism is 10.5 square cm

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Answer: 2.7

Step-by-step explanation:

There are 2.7 bacterias initially hence, option A is correct.

A function is defined as the expression that set up the relationship between the dependent variable and independent variable.

In the graph, we can see that the function is following an exponential curve the initial point in the graph is at ( 0,2.7 ). Then, the initial number of the bacteria is 2.7.

Hence, the hence, option A is correct.

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Answer:

i think 6x

Step-by-step explanation:

cz we have a variable

The answer is 6x

an algebraic expression is an expression solving for a variable. in 6x the variable x is what you would be solving for.

Answer:

The width is 10 inches

The length is 30 inches

Step-by-step explanation:

Perimeter of a Rectangle

The perimeter of a rectangle of length L and width W is calculated as follows:

P = 2L + 2W

It's given the length of a rectangle is 10 more than twice the width:

L = 2W + 10

Substituting into the formula of the perimeter:

P = 2(2W + 10) + 2W

Operating:

P = 4W + 20 + 2W

P = 6W + 20

It's given this perimeter is 80 inches, thus

6W + 20 = 80

Subtracting 20:

6W = 80 - 20 = 60

Dividing by 6:

W = 60 /6 = 10

Since :

L = 2W + 10

L = 2*10 + 10

L = 30

The width is 10 inches

The length is 30 inches

Answer:

51°

Step-by-step explanation:

The sum of the measures of the angles of a triangle is 180°.

x + 60 + x + 82 + 56 = 180

2x + 198 = 180

2x = -18

x = -9

m<A = x + 60 = -9 + 60 = 51

Answer: 51°

l = a x w

Hes trying to find lenth so the equal we be getting a and w's attention

The series [infinity]an n = 1 diverges.

To determine whether the sequence {an} is convergent or divergent, we need to evaluate the limit as n approaches infinity of the sequence. In this case, as n approaches infinity, the value of 3n and 7n grows without bound, while the value of 1 remains constant. Therefore, the sequence {an} diverges.

To determine whether the series [infinity]an n = 1 is convergent, we need to evaluate the sum of the sequence from n = 1 to infinity. The formula for the sum of an arithmetic series is Sn = n(a1 + an)/2, where Sn is the sum of the first n terms, a1 is the first term, and an is the nth term.

In this case, we have an = 3n + 7n + 1, so a1 = 3 + 7 + 1 = 11 and an = 3n + 7n + 1 = 11n + 1. Thus, the sum of the first n terms is Sn = n(11 + (11n + 1))/2 = (11n^2 + 11n)/2 + n/2 = (11/2)n^2 + 6n/2. As n approaches infinity, the dominant term in the sum is the n^2 term, which grows without bound.

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Answer:

It would go 3 to the write of x.

Step-by-step explanation:

If B is the 3 spaces to the left of x and T is three spaces to the right of x, x would be in the middle.

In the picture, you have B=2, X= 5

so T goes if X is the midpoint of BT is

X= (B+T)/2

5 x 2= 2+ T

10 = 2+T

therefore, T = 8

The sample that she must select if she wishes to be 99% confident that the population mean is within 10 minutes of the sample mean = 96

According to the question given,

We will be using the z-distribution to solve the following question.

The level of confidence she wishes to have = is 99%

The mean is within = 10 minutes.

The population standard deviation given is = 38 minutes.

The formula used for the z-distribution,

M = \(z\frac{\sigma }{\sqrt{n} }\) ------ equation 1

So given confidence is = 99%

\(\alpha\) = 0.99

Z = p-value of \(\frac{1+0.99}{2}\)

Z = 0.995

The critical value z will be given as,

z = 2.575

Now we have,

\(\sigma\) = 38

M = 10

Keeping these values in equation 1,

M = \(z\frac{\sigma }{\sqrt{n} }\)

10 = 2.575 x \(\frac{38}{\sqrt{n} }\)

10\(\sqrt{n}\) = 38 x 2.575

\(\sqrt{n}\) = 9.785

n = \((9.785)^{2}\)

n = 95.74

n = 96

Therefore, the sample that she must select if she wishes to be 99% confident that the population mean is within 10 minutes of the sample mean = 96

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Internet Viewing A researcher wishes to estimate the average number of minutes per day a person spends on the Internet. How large a sample must she select if she wishes to be 99% confident that the population means is within 10 minutes of the sample mean?

Assume the population standard deviation is 38 minutes. Round your final answer up to the next whole number.

Answer:

40.7432432432

Step-by-step explanation:

First you multiply 67 and 45 due to order of operations. This gives you 3015. After that you divide by 74 as it is on the right of the equation. 3015 divided by 74 is 40.7432432432

Answer:

been awhile greyfire changed name but its midnight

Step-by-step explanation:

The number -3(5) will equal the -15 which is written in latex as \(-15\) so option (A) will be correct.

Multiplication is the general procedure in mathematics in which we multiply two or more numbers to each other to find a new multiplied number.

Multiplication gives us a resultant number that will be very big as compared to the number which is going to be multiplied if and only if the number which is going to be multiplied is more than one.

Given that, - 3(5)  

since we know in multiplication if you multiply by - and + than the result will be on only - so

-3(5)  = -3×5 = -15 = \(-15\)

Hence, the correct answer will be \(-15\)

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Answer: 3

Step-by-step explanation:

39 divided by 13 is equal to 3

there are 39 days, and if you divide it by how many days (13), you would get how many messages were sent each day which is 3

Well It’s Really Simple You’ve Could Have A Calculator. 52 Fifty- Two

If the eluent were above the 1.5 cm line on the chromatographic paper, it would be considered an unexpected observation.

Normally, during chromatography, the eluent is applied below the baseline or reference line on the paper.

If the eluent exceeds the expected limit and goes above the 1.5 cm line, it can have several implications:

Smearing or spreading: The excess eluent can cause the compounds being separated to spread out more than intended. This can lead to a loss of resolution and poor separation of the individual components.

Incomplete separation: The higher eluent level can disrupt the chromatographic process, resulting in incomplete separation of the compounds. This means that the different components may not be adequately resolved into distinct bands or spots.

Longer analysis time: With the eluent above the expected level, it may take longer for the eluent front to reach the desired distance, as it needs to travel a greater distance on the chromatographic paper. This can increase the overall analysis time and potentially affect the accuracy of the results.

Unreliable measurements: If the eluent exceeds the 1.5 cm line, it can make it challenging to accurately measure the migration distances of the separated compounds. This can introduce uncertainty or errors in the calculations or interpretations of the chromatogram.

In summary, if the eluent is observed above the 1.5 cm line on the chromatographic paper, it is an unexpected observation that can lead to compromised separation, longer analysis times, and potential difficulties in accurate measurements and interpretations of the chromatogram.

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Answer:

900

Step-by-step explanation:

Answer:

Parallel Lines:

y = 6x

y = 6x + 7

Step-by-step explanation:

If they have the same slope, then they are parallel.