cross-sectional designs have a high degree of internal validity because they show how causal processes occur over time. True or false?

Answer:

The correct graph is graph B.

So, 0.25 or 25% of the radium sample will remain after 3240 years.

The decay chain for radium-226 is as follows: radium-226 has a half-life of 1600 years and produces an alpha particle and radon-222; radon-222 has a half-life of 3.82 days and produces an alpha particle and polonium-218; polonium-218 has a half-life of 3.05 minutes and produces an alpha particle and lead-214; lead-214 has a half-life of 26.8 minutes and produces.

The half-life of radium is 1620 years, which means that after 1620 years, half of the radium sample will decay, and the remaining half will remain. After another 1620 years (3240 years total), the remaining half will decay, and half of that half, or one-fourth of the original sample, will remain.

Therefore, after 3240 years, the fraction of the radium sample that will remain is:

Formula used :[tex]N(t)=2^{-t/1620}[/tex]

[tex]N(t)=2^{-3240/1620}[/tex]

= 1/4

= 0.25

Learn more about radium visit: brainly.com/question/31436084

#SPJ4

The value of c on the interval (5,9) such that f'(c) = f(b) - f(a) / (b - a) is c = 3, and the average rate of change of f(x) on the interval [5,9] is 139.

First, we can find the average rate of change of f(x) on the interval [a,b] using the formula:

average rate of change = [f(b) - f(a)] / (b - a)

Substituting the given values of a = 5 and b = 9 into the formula, we get:

average rate of change = [f(9) - f(5)] / (9 - 5)

Next, we need to find f(9) and f(5) to calculate the average rate of change. To do this, we first need to find the derivative of f(x) using the power rule:

f'(x) = 6x² - 6x - 12

Now, we can use the Mean Value Theorem to find a value c in the interval (5,9) such that f'(c) equals the average rate of change. According to the Mean Value Theorem, there exists a value c in the interval (5,9) such that:

f'(c) = [f(9) - f(5)] / (9 - 5)

Substituting the derivative of f(x) and the values of f(9) and f(5) into the equation, we get:

6c² - 6c - 12 = [2(9)³ - 3(9)² - 12(9) - 4 - (2(5)³ - 3(5)² - 12(5) - 4)] / (9 - 5)

Simplifying the right-hand side of the equation, we get:

6c² - 6c - 12 = (658 - 204) / 4

6c² - 6c - 12 = 114

6c² - 6c - 126 = 0

Dividing both sides by 6, we get:

c² - c - 21 = 0

Using the quadratic formula, we can solve for c:

c = [1 ± sqrt(1 + 4(21))] / 2

c = [1 ± 5] / 2

The two possible values of c are:

c = 3 or c = -4

However, since the interval is (5,9), c must be between 5 and 9. Therefore, the value of c that satisfies the Mean Value Theorem is c = 3.

Finally, substituting f(5) and f(9) into the formula for the average rate of change, we get:

average rate of change = [f(9) - f(5)] / (9 - 5)

= [(2(9)³ - 3(9)² - 12(9) - 4) - (2(5)³ - 3(5)² - 12(5) - 4)] / (9 - 5)

= [434 - (-104)] / 4

= 139

Therefore, the value of c on the interval (5,9) such that f'(c) = f(b) - f(a) / (b - a) is c = 3, and the average rate of change of f(x) on the interval [5,9] is 139.

Learn more about the average rate of change at

https://brainly.com/question/28744270

#SPJ4

The number of ways to color an nxn floor with k colors for an even integer n is:

4 * k^(n^2/4).

To determine the number of ways to color an nxn floor with k colors for an even integer n, and considering two colorings to be the same if obtained by rotating the grid, we need to follow these steps:

1. Identify the even integer n and the number of colors k.
2. Calculate the number of unique configurations considering rotations. For a grid of size nxn, there are 4 unique rotations (0, 90, 180, and 270 degrees).
3. For each unique rotation, calculate the number of possible colorings. Since each tile in the grid can be any of the k colors, the number of colorings for each unique rotation is k^(n^2/4), assuming n is divisible by 4.
4. Add up the colorings for all unique rotations. Since there are 4 unique rotations, the total number of colorings, considering rotations to be the same, is 4 * k^(n^2/4).

So, the number of ways to color an nxn floor with k colors for an even integer n, considering two colorings to be the same if obtained by rotating the grid, is 4 * k^(n^2/4).

To learn more about permutations visit : https://brainly.com/question/1216161

#SPJ11

The equation of the circle with center (-3, -5) and radius 4 is (x + 3)² + (y + 5)² = 16.

The standard form equation of a circle with center (h, k) and radius r is:

(x - h)² + (y - k)² = r²

Given that the center of the circle is (-3, -5) and the radius is 4.

Hence, we can substitute these values into the formula to get the equation of the circle:

Plug in h = -3, k = -5 and r = 4

(x - h)² + (y - k)² = r²

(x - (-3))² + (y - (-5))² = 4²

Simplifying and expanding the equation, we get:

(x + 3)² + (y + 5)² = 16

Therefore, the equation of the circle is (x + 3)² + (y + 5)² = 16.

Option B) (x + 3)² + (y + 5)² = 16 is the correct answer.

Learn more about equation of circle here: brainly.com/question/29288238

#SPJ1

The equation of the line that is parallel to 2y = 3x - 1 and passes through the point (4, 2) is: y = (3/2)x - 4

To find the equation of a straight line that is parallel to the line 2y = 3x - 1, we need to remember that parallel lines have the same slope.

First, let's rearrange the given equation into slope-intercept form, y = mx + b, where m is the slope and b is the y-intercept:

2y = 3x - 1

y = (3/2)x - 1/2

So the slope of this line is 3/2.

Now, if we want to find the equation of a line that is parallel to this line, we just need to use the same slope. Let's call the new line y = mx + b, where m is the slope we just found and b is the y-intercept we need to find.

So the equation of the parallel line is:

y = (3/2)x + b

To find the value of b, we need to use a point on the line. Let's say we want the line to go through the point (4, 2):

2 = (3/2)(4) + b

2 = 6 + b

b = -4

So the equation of the line that is parallel to 2y = 3x - 1 and passes through the point (4, 2) is: y = (3/2)x - 4

To know more about   straight line, here

https://brainly.com/question/25969846

#SPJ4

The total amount of commission is 660 dollars.

Given that,

3 percent on sales up to $2,000.00

Commission = 3% of 2000

= 3/100 × 2000

= $60

5 percent on sales from $2,000.00 to $4,000.00

Commission = 5% of 4000

= 5/100 × 5000

= $250

7 percent on sales over $4,000.00

Commission = 7% of 4000

= 7/100 × 5000

= $350

Total commission=60+250+350

= $660

Therefore, the total amount of commission is 660 dollars.

To learn more about the percentage visit:

brainly.com/question/24159063.

#SPJ1

In the given circle, the length of major arc LNM is 29/3(π)

From the question, we are to calculate the length of the major arc in the given diagram

Length of an arc is given by the formula

Length = θ/360° × 2πr

Where θ is the angle subtended by the arc at the center of the circle

r is the radius of the circle

From the given information,

r = 6 cm

θ = 360° - 70°

θ = 290°

Substitute the parameters into the formula

Length = 290/360 × 2×π×6

Length = 29/3(π)

Hence,

Length of arc LNM is 29/3(π)

Learn more on Calculating length of an arc here: https://brainly.com/question/31314204

#SPJ1

Answer:

use desmos cant add pcitures

Step-by-step explanation:

The line 13x - 14y = 70 expressed in slope-intercept form is y = (13/14)x - 5.

Here are the steps to follow:

Step 1: Start with the given equation, which is in standard form: 13x - 14y = 70.

Step 2: Solve for y to put it in slope-intercept form (y = mx + b, where m is the slope and b is the y-intercept).

First, subtract 13x from both sides of the equation:
-14y = -13x + 70

Next, divide both sides by -14:
y = (13/14)x - 5

Learn more about slope-intercept form: https://brainly.com/question/1884491

#SPJ11

The probability of tossing 3 coins of uniform texture at the same time, and two of them happen to be heads up is [tex]\frac{3}{8}[/tex] or 0.375.

The probability of tossing 3 coins of uniform texture at the same time, and two of them happen to be heads up is as follows:

1. Each coin has 2 possible outcomes: heads (H) or tails (T).
2. Since there are 3 coins, there are [tex]2^3 = 8[/tex] total possible outcomes (HHH, HHT, HTH, THH, HTT, THT, TTH, TTT).
3. We're interested in the outcomes where 2 coins are heads up: HHT, HTH, THH.
4. There are 3 favorable outcomes out of 8 total outcomes.

So, the probability of tossing 3 coins of uniform texture at the same time, and two of them happen to be heads up is 3/8 or 0.375.

To know more about probability visit:

https://brainly.com/question/16988487

#SPJ11

If T is an unbiased estimator, then the MSE can be decomposed as follows: MSE(T) = Var(T) + [E(T)-0]^2 = Var(T). Therefore, (d) is true.

(a) E(T-0)^2=Var(T) + [E(T)-0]^2, which is always greater than or equal to 0, but it may not necessarily be 0 unless T is a constant function. Therefore, (a) is false in general.

(b) If E(T-0)=0, then T is an unbiased estimator of 0. This statement is true.

(c) E(T-ET)^2=Var(T) is always greater than or equal to 0, but it may not necessarily be 0 unless T is a constant function. Therefore, (c) is false in general.

(d) The Mean Squared Error (MSE) of T is defined as MSE(T) = E[(T-0)^2]. If T is an unbiased estimator, then the MSE can be decomposed as follows: MSE(T) = Var(T) + [E(T)-0]^2 = Var(T). Therefore, (d) is true.

To learn more about decomposed visit:

https://brainly.com/question/28896356

#SPJ11

The value of the angle m<QPS cannot be determined. Option D

To determine the value of the angle, we need to take note of the properties of a parallelogram

From the information given, we have that;

m<R = 6x -14

m<Q = 3x + 8

m< S= 5x + 4

The value of the angle , QPS cannot be determined because the angle is not represented with any variable for calculation

Learn more about parallelogram at: https://brainly.com/question/10744696

#SPJ1

The graph is misleading because the y values are not labeled

The graph represents the given parameter where

Examining the y-axis of the graph, we can see that

The y-axis is not labeled

This means that

We cannot determine what the y values represent

This is because not labelling  the y-axis do not show the correct representation of the graph

Read more about graphs at

https://brainly.com/question/24741444

#SPJ1

Nolan bought 2 apples and 10 bananas.

To solve this problem form the system of equations first, then solve them to find the values of the variables.

Nolan bought 2 apples and 10 bananas.

It's given that,

Nolan and his children bought fruits (Apples and bananas) worth $8.

Cost of each apple and bananas are $2 and $0.40 respectively.

Let the number of bananas he bought = y

And the number of apples = x

Therefore, cost of the apples =$2x

And the cost of bananas = $0.40y

Total cost of 'x' apples and 'y' bananas = $(2x + 0.40y)

Equation representing the total cost of fruits will be,

(2x + 0.40y) = 8

10(2x + 0.40y) = 10(8)

20x + 4y = 80

5x + y = 20 --------(1)

If he bought 5 times as many bananas as apples,

y = 5x ------(2)

Substitute the value of y from equation (2) to equation (1),

5x + 5x = 20

10x = 20

x = 2

Substitute the value of 'x' in equation (2)

y = 5(2)

y = 10

Therefore, Nolan bought 2 apples and 10 bananas.

Learn more variables,

https://brainly.com/question/17344045

#SPJ4

Full Question ;

Nolan and his children went into a grocery store and he bought $8 worth of apples

and bananas. Each apple costs $2 and each banana costs $0.40. He bought 5 times as

many bananas as apples. By following the steps below, determine the number of

apples, 2, and the number of bananas, y, that Nolan bought.

Answer:

r=3 to dilation

Step-by-step explanation:

([[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[]]]]]]]]]]]]]]]]]]]]]]]]]]]])

Rounding to the nearest tenth of a gallon, we have that the cooler can hold about 74.0 gallons of water.

The volume of a cylinder is given by the formula V = πr^2h, where r is the radius of the base and h is the height.

In this case, the diameter of the cooler is 30 inches, which means the radius is 15 inches (since the radius is half the diameter). The height is 24 inches.

Using the formula for the volume of a cylinder, we have:

V = π[tex]r^2h[/tex]

= π([tex]15^2)(24[/tex])

= 5400π cubic inches

To convert cubic inches to gallons, we need to divide by the conversion factor 231 cubic inches per gallon. Therefore, the volume of the cooler in gallons is:

[tex]V_gal[/tex]= (5400π cubic inches) / (231 cubic inches/gallon) ≈ 74.0 gallons

Rounding to the nearest tenth of a gallon, we have that the cooler can hold about 74.0 gallons of water.

To know more about volume here

https://brainly.com/question/463363

#SPJ4

False. A set is considered closed under an operation if the result of that operation on any two elements in the set also belongs to the set.

A set is considered closed if it contains all of its limit points. In other words, if a sequence of points in the set converges to a point that is also in the set, then the set is closed. Another equivalent definition is that the complement of the set.

In mathematics, sets are collections of distinct objects. These objects can be anything, including numbers, letters, or even other sets. The concept of sets is fundamental in mathematics and is used to define many other mathematical structures.

Sets can be denoted in various ways, including listing the elements inside curly braces { }, using set-builder notation, or using set operations to define new sets from existing ones. Some common set operations include union, intersection, difference, and complement.

To learn more about Set visit:

https://brainly.com/question/18877365

#SPJ4

Answer:

The alternating series test states that if the terms of an alternating series decrease in absolute value and approach zero, then the series converges.

For the power series (r - 5)^n/22 with radius of convergence 2, the alternating series test can be used at x = 2 and x = -2. This is because the alternating series test requires the terms to decrease in absolute value, and for values of x beyond the radius of convergence, the terms of the series increase in absolute value and do not approach zero.

For the given alternating series:

1/4 - 1/2 + 1/8 - 2/720 + 1/16 - ...

The terms decrease in absolute value and approach zero, so the alternating series test can be used to verify convergence.

1/6 + 5/13 + ... + a_n

Since a_n is odd and greater than 3, the terms do not alternate in sign and the alternating series test cannot be used to verify convergence.

(-1)^n (2n+1)/(n+1)

The terms decrease in absolute value and approach zero, so the alternating series test can be used to verify convergence.

Step-by-step explanation:

The answer is D, I and II only. The alternating series test can be used to verify convergence of an alternating series, which means the signs of the terms alternate.

In the given power series (r-5) ^22, there is no alternating pattern of signs, so the alternating series test cannot be used to verify convergence of this series at any value of x. Therefore, the answer is none of the options provided (N/A).

For the second part of the question, we need to check each series to see if they have an alternating pattern of signs. The first series (1/4^n) has all positive terms, so the alternating series test cannot be used to verify convergence of this series. The second series (-1)^n(1/2^n) has alternating signs, so the alternating series test can be used to verify convergence of this series. The third series (-1)^n(1/(4n+1)) also has alternating signs, so the alternating series test can be used to verify convergence of this series. Therefore, the answer is D, I and II only.

Learn more about alternating series here:

brainly.com/question/30761258

#SPJ11

It would take 4 pipes with a radius of 4cm to replace one pipe with a radius of 8cm and provide the same amount of water flow.

We have,

The volume of water that can flow through a pipe is proportional to the cross-sectional area of the pipe.

The formula for the area of a circle is:

A = πr²

where A is the area of the circle and r is the radius of the circle.

For a pipe with a radius of 8cm, the cross-sectional area is:

A_8cm = π(8cm)²

     = 64π cm²

For a pipe with a radius of 4cm, the cross-sectional area is:

A_4cm = π(4cm)²

     = 16π cm²

To find out how many 4cm pipes would be needed to replace one 8cm pipe, we can compare the areas of the two pipes:

Number of 4cm pipes

= A_8cm / A_4 cm

= (64π) / (16π)

= 4

Therefore,

It would take 4 pipes with a radius of 4cm to replace one pipe with a radius of 8cm and provide the same amount of water flow.

Learn more about pipes here:

https://brainly.com/question/31180984

#SPJ1

the probability that the sample mean amount spent on non-medical mask is greater than 22 dollars but less than 25 dollars is approximately 0.0668.

We can use the central limit theorem to approximate the sampling distribution of the sample mean. The mean of the sampling distribution of the sample mean is equal to the population mean, which is 28 dollars, and the standard deviation of the sampling distribution of the sample mean is equal to the standard deviation of the population divided by the square root of the sample size, which is 8/sqrt(36) = 4/3 dollars.

Now we need to find the probability that the sample mean is greater than 22 dollars but less than 25 dollars. Let X be the sample mean amount spent on non-medical mask. Then we need to find P(22 < X < 25).

We can standardize X as follows:

Z = (X - μ) / (σ / sqrt(n))

where μ = 28, σ = 8, and n = 36.

Substituting the values, we get:

Z = (X - 28) / (8/√36)

Z = (X - 28) / (4/3)

So we need to find P((22 - 28)/(4/3) < Z < (25 - 28)/(4/3)), which simplifies to P(-4.5 < Z < -1.5).

Using a standard normal table or calculator, we find:

P(Z < -1.5) ≈ 0.0668

P(Z < -4.5) ≈ 0.00003

Therefore, P(-4.5 < Z < -1.5) ≈ 0.0668 - 0.00003 ≈ 0.0668.

So the probability that the sample mean amount spent on non-medical mask is greater than 22 dollars but less than 25 dollars is approximately 0.0668.

To learn more about probability visit:

https://brainly.com/question/15124899

#SPJ11

The ordered pair (1, -4) is the solution of equation 5x + 2y = -3.

We can check which of the ordered pairs is a solution of equation 5x + 2y = -3 by substituting the values of x and y in the equation and checking if it is true.

a. (2, -4)

Substituting x = 2 and y = -4 in 5x + 2y = -3, we get:

5(2) + 2(-4) = 10 - 8 = 2

So, (2, -4) is not a solution to the equation.

Similarly

b. (-4, 2)

5(-4) + 2(2) = -20 + 4 = -16

So, (-4, 2) is not a solution to the equation.

c. (1, -4)

5(1) + 2(-4) = 5 - 8 = -3

So, (1, -4) is a solution to the equation.

d. (-4, 1)

5(-4) + 2(1) = -20 + 2 = -18

So, (-4, 1) is not a solution to the equation.

Therefore, the ordered pair (1, -4) is the solution of equation 5x + 2y = -3.

Learn more about the ordered pair here:

https://brainly.com/question/30805001

#SPJ1

The standard deviation of the random variable B(400, 0.9) is 6 (option E).

To determine the standard deviation of the random variable B(400, 0.9), we need to use the formula for the standard deviation of a binomial distribution:

Standard deviation (σ) = √(n * p * (1 - p))

Here, n is the number of trials (400) and p is the probability of success (0.9). Now, let's calculate the standard deviation step by step:

1. Calculate the probability of failure (1 - p): 1 - 0.9 = 0.1
2. Multiply n, p, and the probability of failure: 400 * 0.9 * 0.1 = 36
3. Calculate the square root of the result: √36 = 6

So, the standard deviation of the random variable B(400, 0.9) is 6 (option E).

Learn more about standard deviation: https://brainly.com/question/23907081

#SPJ11

The difference between the large prism and the small prism is 276 inches cube.

The prisms above are rectangular base prisms. Therefore, the difference between the volume of the large prism and volume of the smaller prism can be calculated as follows:

Volume of the larger prisms  = lwh

where

Therefore,

Volume of the larger prisms  = 6 × 4 × 15

Volume of the larger prisms  = 360 inches³

volume of the smaller prism = 7 × 4 × 3

Volume of the larger prisms  = 28 × 3

Volume of the larger prisms  = 84 inches³

Therefore,

difference of the volume = 360 - 84

difference of the volume = 276 inches³

learn more on volume here: brainly.com/question/22907480

#SPJ1

(a) The mean of the sampling distribution of the sample mean is equal to the population mean, which is y=2.86. So, х = 2.86.

(b) The standard deviation of the sampling distribution of the sample mean is equal to the population standard deviation divided by the square root of the sample size. So, o = 0.23 / sqrt(7) = 0.087.

To learn more about Standard Deviation : https://brainly.com/question/31697586

#SPJ11

X is in Bs(b+1/2c), which implies Br(α+1/2c)⊂Bs(b+1/2c).

a. We want to show that Br(α+2c)⊂Bs(b+2c) given that Br(α)⊂Bs(b).

Let x be any element in Br(α+2c), then we have ||x-(α+2c)|| < r.

Using the triangle inequality, we get:

||x-(α+2c)|| = ||(x-α)-2c|| ≤ ||x-α||+2||c|| < r+2||c|| = 8 (since r > 0 and ||c|| < 4).

So, ||x-α|| < 8 - 2||c|| < 2.

Thus, x is also in Br(α) ⊂ Bs(b), which implies ||x-b|| < r.

Using the triangle inequality again, we have:

||x-(b+2c)|| = ||(x-b)-2c|| ≤ ||x-b||+2||c|| < r+2||c|| = 8.

Therefore, x is in Bs(b+2c), which implies Br(α+2c)⊂Bs(b+2c).

b. We want to show that Br(α+1/2c)⊂Bs(b+1/2c) given that Br(α)⊂Bs(b).

Let x be any element in Br(α+1/2c), then we have ||x-(α+1/2c)|| < r.

Using the triangle inequality, we get:

||x-(α+1/2c)|| = ||(x-α)-1/2c|| ≤ ||x-α||+1/2||c|| < r+1/2||c|| = 4 (since r > 0 and ||c|| < 8).

So, ||x-α|| < 4 - 1/2||c|| < 3.

Thus, x is also in Br(α) ⊂ Bs(b), which implies ||x-b|| < r.

Using the triangle inequality again, we have:

||x-(b+1/2c)|| = ||(x-b)-1/2c|| ≤ ||x-b||+1/2||c|| < r+1/2||c|| = 4.

Therefore, x is in Bs(b+1/2c), which implies Br(α+1/2c)⊂Bs(b+1/2c).

To learn more about Using visit:

https://brainly.com/question/8723368

#SPJ11

The slope of the line passing through (7,1) and (-2,3) is -2/9.

We use the following formula to get the slope of a line through two specified points:

slope = (y2 - y1) / (x2 - x1)

where (x1, y1) and (x2, y2) are the coordinates of the two points.

We can calculate the slope of the line passing through the points (7, 1) and (-2, 3) using this formula:

slope = (3 - 1) / (-2 - 7) = 2 / (-9) = -2/9

Therefore, the slope of the line passing through the points (7, 1) and (-2, 3) is -2/9.

The slope of a line, in geometric terms, is the ratio of the vertical change (rise) to the horizontal change (run). If the slope is negative, the line is decreasing as we move from left to right. With a slope of 2 units downward for every 9 units to the right, the line is sloping downward from left to right.

To know more about the slope,

https://brainly.com/question/1884491

https://brainly.com/question/29044610

To represent the hourly wage of an employee at the antique store, we can use the following equation:
y = 15 + 0.75x
where y represents the worker's hourly wage, and x represents the number of years the employee has worked at the store. In this equation, 15 is the initial hourly wage, and 0.75 is the annual raise.

The equation that shows how a worker's hourly wage, y, depends on the number of years he or she has worked at the store can be written as:

y = 15 + 0.75x

where x represents the number of years the employee has worked at the antique store.

This equation takes into account the starting wage of $15 per hour and the $0.75 raise that the employee receives each year they work at the store.

So, for example, if an employee has worked at the store for 5 years, their hourly wage would be:

y = 15 + 0.75(5) = 18.75

where y represents the worker's hourly wage, and x represents the number of years the employee has worked at the store.

Learn more about Number:

brainly.com/question/17429689

#SPJ11