a researcher wishes to survey student opinions on a proposed increase in fees at her university. she decides to select a sample for telephone interviewing by selecting every 20th name in the student directory. what is this type of sampling called?

Note that the first method has the smaller Mean Absolute Error (MAE) which is 1.75

The mean absolute error (MAE) is defined as the average variance between the significant values in the dataset and the projected values in the same dataset.

The steps to finding the MAE in eah case is

For the 1st method

Absolute error (AE) for day 1 = |23 - 23| = 0

AE for day 2 = |5 - 10| = 5

AE for day 3 = |14 - 15| = 1

AE  for day 4 = |20 - 19| = 1

so MAE = (0 + 5 + 1 + 1) / 4 = 1.75

For the 2nd system,

Absolute error (AE) 1 = |20 - 23| = 3

AE for day 2 = |13 - 10| = 3

AE  for day 3 = |14 - 15| = 1

AE for day 4 = |20 - 19| = 1

So the  MAE = (3 + 3 + 1 + 1) / 4 = 2

We can conclude, hence, that t the first method has the smaller   MAE of 1.75.

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Therefore, it will take approximately 11.67 years for the money to grow from $10,000 to $15,000 at an annual interest rate of 4.5% compounded continuously.

To solve this problem, we can use the continuous compounding formula: A = Pe^(rt), where A is the final amount, P is the initial principal, e is Euler's number (approximately 2.71828), r is the annual interest rate as a decimal, and t is the time in years. We want to find t when A = $15,000 and P = $10,000. Plugging in these values and solving for t, we get:
$15,000 = $10,000e^(0.045t)
1.5 = e^(0.045t)
ln(1.5) = 0.045t
t = ln(1.5)/0.045
t ≈ 11.67 years

Therefore, it will take approximately 11.67 years for the money to grow from $10,000 to $15,000 at an annual interest rate of 4.5% compounded continuously.

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A. From the statistical results, Jack can conclude that there is a statistically significant difference between the life satisfaction of older adults and middle-aged adults. This is evidenced by the t-value of 2.03 and p-value of .047, which fall below the standard cutoffs for statistical significance. The 95% confidence interval also supports this conclusion, as it does not include zero.

B. Based on these results, Jack should reject the null hypothesis and accept the alternative hypothesis that there is a difference in life satisfaction between older adults and middle-aged adults.

C. The "t(58) = 2.03" indicates the t-value of the statistical test, which is a measure of the difference between the means of the two groups divided by the standard error of that difference. In this case, the t-value of 2.03 suggests that the difference in life satisfaction between the two groups is larger than would be expected by chance.

D. The confidence interval tells us that there is a 95% chance that the true difference in life satisfaction between the two groups falls within the range of 0.01 to 1.59. This suggests that the difference between the two groups is likely not due to chance.

E. The effect size (d = .52) tells us that the difference in life satisfaction between the two groups is moderate in magnitude. This suggests that the difference is not only statistically significant but also practically meaningful.

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The slant height of the cone is 24 cm. 

We are given that the surface area of the cone is 252.58 cm' with the radius of 6 cm.

The surface area of the cone is calculated through the equation as;

                   A = πr² + πrl

where r is the radius and l is the slant height.

Now Substituting the known values to the equation,

             252.58 = π(6 cm)² + π(6 cm)(l)

l = 24 cm.

Thus, the slant height of the cone is 24 cm. 

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When testing the claim that σ21≠σ22, the null hypothesis states that the variances of the two populations are equal, while the alternative hypothesis states that the variances are not equal. To test this claim, we use an F-test, which involves calculating the ratio of the variances of the two samples.

If the test statistic is f=1, this means that the ratio of the variances is equal to 1. This indicates that there is no significant difference between the variances of the two populations. In other words, we cannot reject the null hypothesis that the variances are equal.
However, it is important to note that a test statistic of f=1 does not necessarily mean that the two samples are identical. It is possible for two samples to have slightly different variances that still result in a test statistic of f=1. Additionally, a sample size that is too small or too large can affect the accuracy of the F-test.
Overall, if the test statistic is f=1 when testing the claim that σ21≠σ22, we can conclude that there is not enough evidence to support the alternative hypothesis that the variances are different.

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The area of the rectangle based on the information given is A = 2 / (x - 3)

Length: (x² + 7x + 12) / (5x² - 45)

We can factor the numerator and denominator to simplify:

(x + 3)(x + 4) / 5(x - 3)(x + 3)

The (x + 3) factors cancel out, leaving:

(x + 4) / 5(x - 3)

Width: (10x - 10) / (x² + 3x - 4)

We can factor the denominator to simplify:

(x + 4)(x - 1)

So the width becomes:

10(x - 1) / (x + 4)(x - 1)

The (x - 1) factors cancel out, leaving:

10 / (x + 4)

Now we can multiply the length and width to get the area:

[(x + 4) / 5(x - 3)] * [10 / (x + 4)]

The (x + 4) factors cancel out, leaving:

2 / (x - 3)

The area of the rectangle is:A = 2 / (x - 3)

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The area of the triangle is given by the formula:

A =  (3/2)x² + 11x - 8

Which is the one in option b.

Remember that for a triangle of base B and height H, the area is given by the formula:

A = B*H/2

Here we know that the height is:

H = 8 + x

The base is:

B = 3x - 2

Then the area of the triangle is:

A = (8 + x)*(3x - 2)/2

A = (24x - 16 + 3x² - 2x)/2

A = (3x² + 22x - 16)/2

A = (3/2)x² + 11x - 8

Then the correct option is B (though the constant term is -8 instead of -9)

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81 can be written as 3^4 and 64 can be written as 2^6. There are several ways to write 81 and 64 using exponents. For example:

- 81 = 3^4 = (3^2)^2

- 81 = 9^2/3 = (3^2)^2/3

- 81 = (27/3)^2 = 27^(2/3)

- 64 = 2^6 = (2^3)^2

- 64 = 4^3/2 = (2^2)^3/2

- 64 = (8/2)^3 = 8^(3/2)

To write 64/81 using exponents, we can use the fact that a fraction can be written as a negative exponent. Therefore,

- 64/81 = 64 * 81^(-1) = 2^6 * 3^(-4) = 2^6/3^4

- 64/81 = (2/3)^(-6/4) = (2/3)^(-3/2)

- 64/81 = 8^2/9^2 = (8/9)^2

These are some examples of how to write 64/81 using exponents. It is important to note that there are infinitely many ways to write a number using exponents, but some forms may be more useful or appropriate in certain situations.

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The ice cream shop could order a different size scoop with a diameter closer to 1.732 in for an even better fit.

Ice cream scoop will be the best fit for the waffle cones need to find out the diameter of the cones.

We can use the given height and volume of the cones to calculate the diameter using the formula for the volume of a cone:

V = (1/3) × π × r² × h

V is the volume r is the radius (which is half the diameter) and h is the height.

Rearranging the formula to solve for r we get:

r = √((3V) / (πh))

Substituting the given values of V = 3π in³ and h = 4 in we get:

r = √((3π) / (4π))

= √(3/4)

= 0.866 in

So, the diameter of the waffle cones is approximately 1.732 in (twice the radius).

Now we can compare this diameter to the diameters of the #12 and #6 scoops.

The #12 scoop has a diameter of 2.5 in is larger than the cone diameter of 1.732 in so it may not be the best fit.

The #6 scoop has a diameter of 3 in is larger than the cone diameter but closer in size so it may be a better fit than the #12 scoop.

The ice cream shop could order a different size scoop with a diameter closer to 1.732 in for an even better fit.

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Answer:

you got them all correct! good job :)

Step-by-step explanation:

The enlarged photograph will be 30 inches in width and a proportional length.

Marine has a rectangular photograph that measures 6 inches in width. If she wants to enlarge the photograph using a scale of 1:5, this means that the size of the photograph will be increased by a factor of 5 in both width and height.

To determine the new width of the photograph, we can multiply the original width of 6 inches by 5, which gives us a width of 30 inches for the enlarged photograph.

It's important to note that while the width of the photograph will increase, the aspect ratio of the photograph will remain the same.

This means that the length of the photograph will also be increased by the same factor of 5.

Therefore, the enlarged photograph will be 30 inches in width and a proportional length.

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Using Euler's method with a time step of 0.3, the first two approximations for the solution to the initial value problem y'(t) = t + y, y(0) = 5 are u1 = 6.5 and u2 = 8.035.

Using Euler's method, we can approximate the solution to the initial value problem y'(t) = t + y, y(0) = 5 with a time step of Δt = 0.3 as follows:

At t = 0, y = 5

Using the formula: y1 = y0 + f(y0,t0)Δt, where f(y,t) = t + y

y1 = 5 + (0 + 5)0.3 = 6.5

Using the formula again with y1 and t1 = Δt:

y2 = 6.5 + (0.3 + 6.5)0.3 = 8.035

Thus, the first two approximations u1 and u2 are 6.5 and 8.035, respectively.

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The margin of error at 95% confidence is approximately 2.16.

What is the mean and standard deviation?

The standard deviation is a summary measure of the differences of each observation from the mean. If the differences themselves were added up, the positive would exactly balance the negative and so their sum would be zero. Consequently, the squares of the differences are added.

To find the margin of error at 95% confidence, we need to use the following formula:

Margin of error = z * (σ/√n)

where:

z = the z-score associated with the desired level of confidence (in this case, 95% confidence corresponds to a z-score of 1.96)

σ = the population standard deviation

n = the sample size

Given that the population variance is 441, the population standard deviation is the square root of 441, which is 21.

So, the margin of error is:

Margin of error = 1.96 * (21/√361)

= 1.96 * (21/19)

= 2.16 (rounded to two decimal places)

Therefore, the margin of error at 95% confidence is approximately 2.16.

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The work done by force f in moving a particle counterclockwise around the given curve is zero.

The given force [tex]f = (x-5y)i + (5x-y)j[/tex] is a conservative force. A conservative force is characterized by having a curl of zero, indicating that it can be derived from a potential function. For conservative forces, the work done over a closed path is always zero.

In this case, the particle moves counterclockwise around the circle defined by [tex](x-4)^2 + (y-4)^2 = 16[/tex]. Since the force f is conservative, the work done by f on the particle is independent of the path taken and depends only on the initial and final positions of the particle.

As the particle completes one counterclockwise revolution around the circle, it returns to its initial position. Therefore, the work done by force f is zero, indicating that the force does not transfer any energy to or from the particle.

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The solution is: The General Solution of the expression is: Cos x = 2/3

Here, we have,

Explanation:

Given expression:

3sinx = 2tanx​

Find:

Simplify expression......

Computation:

By taking given trigonometric equation

⇒ 3sinx = 2tanx​

Using substitution method...

⇒ sinx = [2/3]tax

⇒ sinx / tanx = 2/3

⇒ sinx / [sinx / cosx] = 2/3

⇒ [sinx × cosx] / sinx = 2/3

⇒ cosx = 2/3

Simplify expression

Cos x = 2/3

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complete question:

Determine the general solution of 3sin x=2tan x​

The solution of the two system of equations using elimination method is x = 8, and y = 3.

The solution of the two system of equations using elimination method is calculated as follows;

The given equations;

2x - 5y = 1   -------- (1)

-3x + 2y = -18 ----- (2)

To eliminate x, multiply equation (1)  by 3 and equation (2) by 2, and add the to equations together;

3:   6x  -  15y = 3

2:   -6x  + 4y  = -36

-----------------------------------

             -11y = -33

               y = 33/11  =  3

Now, solve for the value of x by substituting the value of y back into any of the equations.

2x - 5y = 1

2x - 5(3) = 1

2x - 15 = 1

2x = 16

x = 8

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The given power series is ∑n=1infinity/n! and we need to find its convergence set. This series converges for -∞ < x < ∞.

The given power series is ∑n=1infinity/n!. To find its convergence set, we can use the ratio test. Applying the ratio test, we get:

lim [n→∞] |(2^(n+1) x^(n+1))/(n+1)!| / |(2^n x^n)/n!|

= lim [n→∞] (2x)/(n+1)

= 0

Since the limit is less than 1 for all values of x, the series converges for all values of x. Therefore, the convergence set is (-∞, ∞).

Intuitively, we can see that since the terms of the series involve a factorial in the denominator, the terms become smaller and smaller as n increases, making it easier for the series to converge. In addition, the term 2^n in the numerator increases rapidly, which can balance out the effect of the denominator. As a result, the series converges for all values of x.

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Note that the probability of randomly selecting one person from this table and the person being a female is 50 %.

Given that we have 10 high school girls and 10 women.

Therefore, the total number of females is 10 ( girls)   + 10 (women) =  20.

For the  total number of people in the sample, we have 10 high school boys, 10 high school girls, 10 men, and 10 women, which  sums up to 10 + 10 + 10 + 10 = 40.

Probability = Number of females / Total number of people

= 20 / 40

= 0.5 or 50%

Thus, the probability of randomly selecting one person from the table and the person being a female is 50%.

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One possible square root of 340 modulo 437 is 281.

To find a square root of a number modulo another number, we can use the Tonelli-Shanks algorithm. First, we check that 340 is a quadratic residue modulo 437 by calculating 340^((437-1)/2) mod 437, which gives 1. Then we can choose a starting value for the square root, such as 281, and use the Tonelli-Shanks algorithm to iteratively improve our estimate. After a few iterations, we should arrive at a more precise square root. Note that there may be multiple square roots, and this is just one example.

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a. The Median age is 43

b. Youngest employee: 34

Oldest employee: 61

c. The lower quartile (Q1) is the median of the lower half of the sorted list, and the upper quartile (Q3) is the median of the upper half. The interquartile range (IQR) is the difference between Q3 and Q1.

a. The median age is the middle value when the ages are sorted. Since there are 21 employees, the median will be the 11th value:

Median age = 43

b. The youngest employee is the first value in the sorted list, and the oldest employee is the last value:

Youngest employee: 34

Oldest employee: 61

c. The lower quartile (Q1) is the median of the lower half of the sorted list, and the upper quartile (Q3) is the median of the upper half. The interquartile range (IQR) is the difference between Q3 and Q1.

Lower quartile (Q1) = Median of the lower half = (36 + 37) / 2 = 36.5

Upper quartile (Q3) = Median of the upper half = (51 + 54) / 2 = 52.5

Interquartile range (IQR) = Q3 - Q1 = 52.5 - 36.5 = 16

d. To sketch a box plot, we can represent the minimum, maximum, Q1, Q3, and median values on a number line:

Minimum: 34

Q1: 36.5

Median: 43

Q3: 52.5

Maximum: 61

The box plot will have a box from Q1 to Q3 with a line inside representing the median. The whiskers will extend from Q1 to the minimum and from Q3 to the maximum.

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To represent the relationship between the height of the waterfall and the height of its picture on a postcard, we can use the equation y = 7n.The correct answer is option A.

Here, 'y' represents the height of the waterfall, and 'n' represents the factor by which the waterfall is taller than the picture.

The equation states that the height of the waterfall, 'y', is equal to 7 multiplied by 'n'. Since the picture on the postcard is 7 cm tall, multiplying it by 'n' gives us the height of the waterfall.

For example, if the factor 'n' is 3, the height of the waterfall would be 7 cm * 3 = 21 cm. If 'n' is 5, the height would be 7 cm * 5 = 35 cm. The equation allows us to calculate the height of the waterfall for any given factor 'n'.

Using this equation, we can determine the height of the waterfall based on the height of its picture on the postcard, providing a simple and direct relationship between the two.

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The probable question may be:

A waterfall is n times the height of its picture on a postcard. Which equation represents the height, y, of the waterfall if the picture is 7 cm tall?

A. y = 7n

B. y = 7 + n

C. y = n - 7

D. y = 7 / n

The volume V of the solid S can be found using the formula for the volume of a cone, which is V = (1/3)πr^2h, where r is the radius of the base and h is the height of the cone.

In this case, the height of the cone is 3h and the base radius is 3r, so we have r = 3r and h = 3h. Substituting these values into the formula, we get:

V = (1/3)π(3r)^2(3h)

V = 27πr^2h

Therefore, the volume of the solid S is 27πr^2h.

To explain further, we can see that the solid S is a cone with a height that is three times the given height and a base radius that is three times the given radius. The volume of any cone can be found using the formula V = (1/3)πr^2h, where r is the radius of the base and h is the height of the cone. By substituting the given values of r and h into this formula, we can obtain the volume of the cone. In this case, we have to substitute 3r for r and 3h for h to get the volume of the solid S in terms of the given height and radius. Simplifying the expression, we get the final answer as 27πr^2h.

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To convert polar coordinates (r,θ) to rectangular coordinates (x,y). Therefore, the rectangular coordinates of the point with polar coordinates (1,116) are approximately (-0.211, 0.978).

we use the following formulas:

x = r cos(θ)

y = r sin(θ)

In this case, the polar coordinates are (1,116). Therefore, we have:

r = 1

θ = 116°

Converting θ from degrees to radians, we get:

θ = 116° * π/180 = 2.025 radians

Substituting these values into the formulas above, we get:

x = r cos(θ) = 1 cos(2.025) ≈ -0.211

y = r sin(θ) = 1 sin(2.025) ≈ 0.978

Therefore, the rectangular coordinates of the point with polar coordinates (1,116) are approximately (-0.211, 0.978).

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Step-by-step explanation:

A semi-circle is half of a circle. Therefore, to find the area of a semi-circle, you just have to find the area of a full circle and then divide it by two. It will be faster than you think.[1]

Using an equation, the commission percentage (x) that you earn if you work 8 hours with sales of $1,400 and total earnings of $176 for the day is 4%.

The commission percentage can be determined by equating the normal earnings for the day and the sales commission to the total earnings.

An equation represents two or more mathematical expressions using the equal symbol.

The hourly rate of earnings = $15

The number of hours worked for the day = 8 hours

The commission percentage = x

The Sales for the day = $1,400

The total earnings for the day = $176

Total earnings = hourly rate x 8 hours + 1,400x

176 = 15 x 8 + 1,400x

176 = 120 + 1,400x

56 = 1,400x

x = 0.04

x = 4%

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The value of the integral ∫[4,-2]f(x)8 dx is -576.

If the average value of a continuous function f on the interval [−2, 4] is 12, it means that the definite integral of f(x) over the interval [−2, 4] is equal to 12 times the length of the interval, which is 6. In other words:

∫[-2,4]f(x) dx = 12(4-(-2)) = 72

Now we can use this information to evaluate the integral ∫[4,-2]f(x)8 dx. We can use the constant multiple rule of integration to pull out the constant 8 from the integral:

∫[4,-2]f(x)8 dx = 8 ∫[4,-2]f(x) dx

Since we already know that ∫[-2,4]f(x) dx = 72, we can evaluate the integral over the interval [4,-2] using the property of definite integrals that says:

∫[a,b]f(x) dx = -∫[b,a]f(x) dx

Therefore:

∫[4,-2]f(x) dx = -∫[-2,4]f(x) dx = -72

Substituting this value back into the original expression, we get:

∫[4,-2]f(x)8 dx = 8 ∫[4,-2]f(x) dx = 8(-72) = -576

Therefore, the value of the integral ∫[4,-2]f(x)8 dx is -576.

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The approximate demand when the price is decreased to $2.25 is 4,800 boxes.

We know that demand is inversely proportional to price, so we can set up the following equation:

x ∝ 1/p

If x denotes demand and p denotes price. We can introduce a proportionality constant k to this equation:

x = k/p

Using the information in the problem, we can calculate the value of k. The demand is 1,800 boxes when the price is $6:

1,800 = k/6

Solving for k, we get:

k = 6 x 1800

k = 10,800

Now we can use this value of k to find the demand when the price is $2.25:

x = 10,800/2.25

x ≈ 4,800

Therefore, the approximate demand when the price is $2.25 is 4,800 boxes.

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To determine whether there is evidence that the students who used an online homework system did better on the final exam than those who did not, we can perform a hypothesis test.

State the null hypothesis (H0) and alternative hypothesis (Ha)

H0: There is no difference in the final exam scores between students who used an online homework system and those who did not.

Ha: Students who used an online homework system scored higher on the final exam than those who did not.

Determine the level of significance (alpha). Let's assume a significance level of 0.05.

Collect the data and calculate the sample means and standard deviations for the two groups.

Conduct a t-test for independent samples to determine whether the observed difference in means between the two groups is statistically significant.

If the calculated p-value is less than the significance level (alpha), we can reject the null hypothesis and conclude that there is evidence that the students who used an online homework system did better on the final exam than those who did not. If the p-value is greater than alpha, we fail to reject the null hypothesis and conclude that there is not enough evidence to suggest that there is a difference in the final exam scores between the two groups.

It's important to note that the results of a hypothesis test depend on the sample size, the variability of the data, and the assumptions made about the underlying population. Therefore, it's important to carefully evaluate the data and assumptions before making any conclusions.

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Answer:

6

Step-by-step explanation:

8+9+1 is 18, and since there are 3 numbers, we must divide 18 by 3, 2 which is 6

Answer: 6

Step-by-step explanation:

8+9+1 = 18
3 numbers
18/3 = 6