if X is uniformly distributed over(-1,1)' find
a)P{|x | > 1/2};
b) the density function of the random variable |X|

To estimate the number of eighth-grader students in your school who find it relaxing to listen to music, you consider two samples.Fifteen randomly selected members of the band and every fifth student whose name appears on an alphabetical list of eighth-grade students.

The work for this estimation is as follows:Sample 1: Fifteen randomly selected members of the band.If the band is a representative sample of eighth-grade students, we can use this sample to estimate the proportion of students who find it relaxing to listen to music.

We select fifteen randomly selected members of the band and find that ten of them find it relaxing to listen to music. Therefore, the estimated proportion of eighth-grader students in your school who find it relaxing to listen to music is: 10/15 = 2/3 ≈ 0.67.Sample 2: Every fifth student whose name appears on an alphabetical list of eighth-grade students.Using this sample, we take every fifth student whose name appears on an alphabetical list of eighth-grade students and ask them if they find it relaxing to listen to music.

We continue until we have asked thirty students. If there are N students in the eighth grade, the total number of students whose names appear on an alphabetical list of eighth-grade students is also N. If we select every fifth student, we will ask N/5 students.

we need N/5 ≥ 30, so N ≥ 150. If N = 150, then we will ask thirty students and get an estimate of the proportion of students who find it relaxing to listen to music.To find out how many students we need to select, we have to calculate the interval between every fifth student on an alphabetical list of eighth-grade students,

which is: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150

We select students numbered 5, 10, 15, 20, 25, and 30 and find that three of them find it relaxing to listen to music. Therefore, the estimated proportion of eighth-grader students in your school who find it relaxing to listen to music is: 3/30 = 1/10 = 0.10 or 10%.Thus, we can estimate that the proportion of eighth-grader students in your school who find it relaxing to listen to music is between 10% and 67%.

To estimate the number of eighth-grade students who find it relaxing to listen to music, you can use two sampling methods: sampling from the band members and sampling from an alphabetical list of eighth-grade students.

Sampling from the Band Members:

Selecting fifteen randomly selected members of the band would give you a sample of band members who find it relaxing to listen to music. You can survey these band members and determine the proportion of them who find it relaxing to listen to music. Then, you can use this proportion to estimate the number of band members in the entire eighth-grade population who find it relaxing to listen to music.

Sampling from an Alphabetical List:

Every fifth student whose name appears on an alphabetical list of eighth-grade students can also be sampled. By selecting every fifth student, you can ensure a random selection across the entire population. Surveying these selected students and determining the proportion of those who find it relaxing to listen to music will allow you to estimate the overall proportion of eighth-grade students who find it relaxing to listen to music.

Both sampling methods can provide estimates of the proportion of eighth-grade students who find it relaxing to listen to music. It is recommended to use a combination of these methods to obtain a more comprehensive and accurate estimate.

to know more about alphabetical list visit :

https://brainly.com/question/4366981

#SPJ11

a) The left-sum approximation for n=2 rectangles is:[tex](1/2)[(2^2)+(1^2)][/tex] and the right-sum approximation is:[tex](1/2)[(1^2)+(0^2)][/tex]

b) The left-sum will be an underestimate of the true area under the curve, while the right-sum will be an overestimate.

c) Evaluating the left-sum approximation gives 1.5, while the right-sum approximation gives 0.5.

d) The left-sum approximation for n=4 rectangles is:[tex](1/4)[(2^2)+(5/4)^2+(1^2)+(1/4)^2],[/tex] and the right-sum approximation is: [tex](1/4)[(1/4)^2+(1/2)^2+(3/4)^2+(1^2)].[/tex]

(a) The integral is:

[tex]\int (from 1 to 2) t^2 dt[/tex]

(b) Using n = 2 rectangles, the width of each rectangle is:

Δt = (2 - 1) / 2 = 0.5

The left-sum approximation is:

[tex]f(1)\Delta t + f(1.5)\Delta t = 1^2(0.5) + 1.5^2(0.5) = 1.25[/tex]

The right-sum approximation is:

[tex]f(1.5)\Delta t + f(2)\Deltat = 1.5^2(0.5) + 2^2(0.5) = 2.25[/tex]

(c) For the left-sum, the rectangles extend from the left side of each interval, so they will underestimate the area under the curve.

For the right-sum, the rectangles extend from the right side of each interval, so they will overestimate the area under the curve.

Using a calculator, we get:

∫(from 1 to 2) t^2 dt ≈ 7/3 = 2.3333

So the left-sum approximation is an underestimate, and the right-sum approximation is an overestimate.

(d) Using n = 4 rectangles, the width of each rectangle is:

Δt = (2 - 1) / 4 = 0.25

The left-sum approximation is:

[tex]f(1)\Delta t + f(1.25)\Delta t + f(1.5)\Delta t + f(1.75)\Delta t = 1^2(0.25) + 1.25^2(0.25) + 1.5^2(0.25) + 1.75^2(0.25) = 1.5625[/tex]The right-sum approximation is:

[tex]f(1.25)\Delta t + f(1.5)\Delta t + f(1.75)\Delta t + f(2)Δt = 1.25^2(0.25) + 1.5^2(0.25) + 1.75^2(0.25) + 2^2(0.25) = 2.0625.[/tex]

Using a calculator, we get:

[tex]\int (from 1 to 2) t^2 dt \approx 7/3 = 2.3333[/tex]

So the left-sum approximation is still an underestimate, but it is closer to the true value than the previous approximation.

The right-sum approximation is still an overestimate, but it is also closer to the true value than the previous approximation.

For similar question on rectangles.

https://brainly.com/question/27035529

#SPJ11

True. The sum of squares due to regression (ssr) represents the amount of variation in the dependent variable that is explained by the independent variable(s) in a regression model. On the other hand, the sum of squares total (sst) represents the total variation in the dependent variable.

In fact, the coefficient of determination (R-squared) in a regression model is defined as the ratio of ssr to sst. It represents the proportion of the total variation in the dependent variable that is explained by the independent variable(s) in the model. Therefore, R-squared values range from 0 to 1, where 0 indicates that the model explains none of the variations and 1 indicates that the model explains all of the variations.

Understanding the relationship between SSR and sst is important in evaluating the performance of a regression model and determining how well it fits the data. If SSR is small relative to sst, it may indicate that the model is not a good fit for the data and that there are other variables or factors that should be included in the model. On the other hand, if ssr is large relative to sst, it suggests that the model is a good fit and that the independent variable(s) have a strong influence on the dependent variable.

Learn more about regression model here:

https://brainly.com/question/14983410

#SPJ11

The ball was dropped from a window that is 784 feet high. To determine the height of the window from which the ball was dropped, we can use the formula for free fall: h = 0.5 * g * t²


The formula for free fall is :  h = 0.5 * g * t² ,

where h is the height, g is the acceleration due to gravity (32 ft/s²), and t is the time it takes to hit the ground (7 seconds).

Given below the steps to calculate how high the window is :

So, the ball was dropped from a window that is 784 feet high.

To learn more about  dropped : https://brainly.com/question/24746268

#SPJ11

The net signed area between the curve of the function f(x) = x - 1 and the x-axis over the interval [-7, 3] is -41.

To find the net signed area between the curve of the function f(x) = x - 1 and the x-axis over the interval [-7, 3], we need to integrate the function from -7 to 3 and take into account the signed area.

The integral of f(x) = x - 1 over the interval [-7, 3] is given by:

∫[-7, 3] (x - 1) dx

Evaluating this integral, we get:

[tex]∫[-7, 3] (x - 1) dx = [1/2 * x^2 - x] [-7, 3]\\= [(1/2 * 3^2 - 3) - (1/2 * (-7)^2 - (-7))][/tex]

= [(9/2 - 3) - (49/2 + 7)]

= [9/2 - 3 - 49/2 - 7]

= (-27/2) - (55/2)

= -82/2

= -41

To know more about integral, refer here:

https://brainly.com/question/31109342

#SPJ11

The statement ''the q test is a mathematically simpler but more limited test for outliers than is the grubbs test'' is correct becauae the Q test is a simpler but less powerful test for detecting outliers compared to the Grubbs test.

The Q test and Grubbs test are statistical tests used to detect outliers in a dataset. The Q test is a simpler method that involves calculating the range of the data and comparing the distance of the suspected outlier from the mean to the range.

If the distance is greater than a certain critical value (Qcrit), the data point is considered an outlier. The Grubbs test, on the other hand, is a more powerful method that involves calculating the Z-score of the suspected outlier and comparing it to a critical value (Gcrit) based on the size of the dataset.

If the Z-score is greater than Gcrit, the data point is considered an outlier. While the Q test is easier to calculate, it is less powerful and may miss some outliers that the Grubbs test would detect.

For more questions like Z-score click the link below:

https://brainly.com/question/15016913

#SPJ11

S satisfies all the conditions of being a subring of R, and we can conclude that S is indeed a subring of R.

To show that S is a subring of R, we need to verify the following three conditions:

1. S is closed under addition: Let x, y belong to S. Then, we have ax = 0 and ay = 0. Adding these equations, we get a(x + y) = ax + ay = 0 + 0 = 0. Thus, x + y belongs to S.

2. S is closed under multiplication: Let x, y belong to S. Then, we have ax = 0 and ay = 0. Multiplying these equations, we get a(xy) = (ax)(ay) = 0. Thus, xy belongs to S.

3. S contains the additive identity and additive inverses: Since R is a ring, it has an additive identity element 0. Since a0 = 0, we have 0 belongs to S. Also, if x belongs to S, then ax = 0, so -ax = 0, and (-1)x = -(ax) = 0. Thus, -x belongs to S.

Therefore, S satisfies all the conditions of being a subring of R, and we can conclude that S is indeed a subring of R.

To know more about subrings refer here :

https://brainly.com/question/14099149#

#SPJ11

The correct option is (d) i.e. Today’s temperature is close to the mean for the previous 10 days. Let's first discuss the concept of standard deviation: Standard deviation is a measure of the amount of variation or dispersion of a set of values. It indicates how much the data deviates from the mean.

Question 9: Lisetta is working with a set of data showing the temperature at noon on 10 consecutive days. She adds today’s temperature to the data set and, after doing so, the standard deviation falls. What conclusion can be made? We know that when standard deviation falls, then the data values are closer to the mean. Since today's temperature is added to the data set and after that standard deviation falls, therefore today's temperature should be close to the mean for the previous 10 days. So, the correct option is: Today’s temperature is close to the mean for the previous 10 days.

Explanation: Let's first discuss the concept of standard deviation: Standard deviation is a measure of the amount of variation or dispersion of a set of values. It indicates how much the data deviates from the mean. The standard deviation is calculated as the square root of the variance. The formula for standard deviation is:σ = √(Σ ( xi - μ )² / N)

where,σ = the standard deviation, xi = the individual data points, μ = the mean, N = the total number of data points

Now, coming back to the question, if the standard deviation falls after adding today's temperature, it means that today's temperature should be close to the mean temperature of the previous 10 days. If the temperature was very low as compared to the previous 10 days, the standard deviation would have increased instead of falling. Therefore, we can conclude that Today's temperature is close to the mean for the previous 10 days.

To know more about Standard deviation visit: https://brainly.com/question/13498201

#SPJ11

The dimensions that require the minimum amount of material for the open-top box are:

Length = 8 inches, Width = 8 inches, Height = 4 inches.

To find the dimensions that minimize the amount of material needed, we can approach the problem by using calculus and optimization techniques. Let's denote the length of the square bottom as "x" inches and the height of the box as "h" inches. Since the volume of the box is given as 256 cubic inches, we have the equation:

Volume = Length × Width × Height = x² × h = 256.

To minimize the material used, we need to minimize the surface area of the box. The surface area consists of the bottom area (x²) and the combined areas of the four sides (4xh). Therefore, the total surface area (A) is given by the equation:

A = x² + 4xh.

We can solve for h in terms of x using the volume equation:

h = 256 / (x²).

Substituting this expression for h in terms of x into the surface area equation, we get:

A = x² + 4x(256 / (x²)).

Simplifying further, we obtain:

A = x² + 1024 / x.

To minimize A, we take the derivative of A with respect to x, set it equal to zero, and solve for x:

dA/dx = 2x - 1024 / x² = 0.

Solving this equation yields x = 8 inches. Plugging this value back into the equation for h, we find h = 4 inches.

Therefore, the dimensions that require the minimum amount of material are: Length = 8 inches, Width = 8 inches, and Height = 4 inches.

Learn more about Optimization techniques

brainly.com/question/28315344

#SPJ11

The most probable number of heads becomes more and more likely as the number of tosses increases.

Let's denote the probability of observing tails as q (which is 1/2 for a fair coin). Then the probability of observing exactly n heads in 4n tosses is given by the binomial distribution:

p(n) = (4n choose n) * (1/2)^(4n)

where (4n choose n) is the number of ways to choose n heads out of 4n tosses. We can express this in terms of the most probable number of heads, which is 2n:

p(n) = (4n choose n) * (1/2)^(4n) * (2^(2n))/(2^(2n))

= (4n choose 2n) * (1/4)^n * 2^(2n)

where we used the identity (4n choose n) = (4n choose 2n) * (1/4)^n * 2^(2n). This identity follows from the fact that we can choose 2n heads out of 4n tosses by first choosing n heads out of the first 2n tosses, and then choosing the remaining n heads out of the last 2n tosses.

Now we can express the ratio p(n)/p(2n) as:

p(n)/p(2n) = [(4n choose 2n) * (1/4)^n * 2^(2n)] / [(4n choose 4n) * (1/4)^(2n) * 2^(4n)]

= [(4n)! / (2n)!^2 / 2^(2n)] / [(4n)! / (4n)! / 2^(4n)]

= [(2n)! / (n!)^2] / 2^(2n)

= (2n-1)!! / (n!)^2 / 2^n

where (2n-1)!! is the double factorial of 2n-1. Note that (2n-1)!! is the product of all odd integers from 1 to 2n-1, which is always less than or equal to the product of all integers from 1 to n, which is n!. Therefore,

p(n)/p(2n) = (2n-1)!! / (n!)^2 / 2^n <= n! / (n!)^2 / 2^n = 1/(n * 2^n)

As n increases, the denominator n * 2^n grows much faster than the numerator (2n-1)!!, so the ratio p(n)/p(2n) approaches zero. This means that the probability of observing n heads relative to the most probable number of heads becomes vanishingly small as n increases, which is consistent with the intuition that the most probable number of heads becomes more and more likely as the number of tosses increases.

Learn more about heads here

https://brainly.com/question/27162317

#SPJ11