Answer:
The p-value of the test is 0.0228, which is less than the standard significance level of 0.05, which means that there is evidence that the proportion of freshmen who graduated in the bottom third of their high school class in 2001 has been reduced.
Step-by-step explanation:
Before solving this question, we need to understand the central limit theorem and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
1999:
20 out of 100 in the bottom third, so:
[tex]p_1 = \frac{20}{100} = 0.2[/tex]
[tex]s_1 = \sqrt{\frac{0.2*0.8}{100}} = 0.04[/tex]
2001:
10 out of 100 in the bottom third, so:
[tex]p_2 = \frac{10}{100} = 0.1[/tex]
[tex]s_2 = \sqrt{\frac{0.1*0.9}{100}} = 0.03[/tex]
Test if proportion of freshmen who graduated in the bottom third of their high school class in 2001 has been reduced.
At the null hypothesis, we test if the proportion is still the same, that is, the subtraction of the proportions in 1999 and 2001 is 0, so:
[tex]H_0: p_1 - p_2 = 0[/tex]
At the alternative hypothesis, we test if the proportion has been reduced, that is, the subtraction of the proportion in 1999 by the proportion in 2001 is positive. So:
[tex]H_1: p_1 - p_2 > 0[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{s}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, and s is the standard error.
0 is tested at the null hypothesis:
This means that [tex]\mu = 0[/tex]
From the two samples:
[tex]X = p_1 - p_2 = 0.2 - 0.1 = 0.1[/tex]
[tex]s = \sqrt{s_1^2 + s_2^2} = \sqrt{0.04^2 + 0.03^2} = 0.05[/tex]
Value of the test statistic:
[tex]z = \frac{X - \mu}{s}[/tex]
[tex]z = \frac{0.1 - 0}{0.05}[/tex]
[tex]z = 2[/tex]
P-value of the test and decision:
The p-value of the test is the probability of finding a difference of at least 0.1, which is the p-value of z = 2.
Looking at the z-table, the p-value of z = 2 is 0.9772.
1 - 0.9772 = 0.0228.
The p-value of the test is 0.0228, which is less than the standard significance level of 0.05, which means that there is evidence that the proportion of freshmen who graduated in the bottom third of their high school class in 2001 has been reduced.
Describe the following sequence using an algebraic expression as a rule 0; 2,4; 6
Answer:
Step-by-step explanation:
I assume the sequence is 0, 2, 4, 6
nth term = 2(n-1)
If you are dealt 4 cards from a shuffled deck of 52 cards, find the probability of getting 2 queens and 2 kings.
The probability is ___.
(Round to six decimal places as needed.)
Answer:
1.083
Step-by-step explanation:
Exact form: 13/12
Decimal form: 1.083 (put a line above the 3)
Mixed number form: 1 1/12
Aubrey's dinner cost $85. She tips the waitstaff 30%, for excellent service.
How much does Aubrey tip the waitstaff?
A sample of 13 sheets of cardstock is randomly selected and the following thicknesses are measured in millimeters. Give a point estimate for the population standard deviation. Round your answer to three decimal places. 1.96,1.81,1.97,1.83,1.87,1.84,1.85,1.94,1.96,1.81,1.86,1.95,1.89
===============================================
Explanation:
Add up the values to get
1.96+1.81+1.97+1.83+1.87+1.84+1.85+1.94+1.96+1.81+1.86+1.95+1.89= 24.54
Then divide over 13 (the number of values) to get 24.54/13 = 1.8876923 which is approximate.
So the mean is approximately 1.8876923
---------------------
Now make a spreadsheet as shown below
We have the first column as the x values, which are the original numbers your teacher provided. The second column is of the form (x-M)^2, where M is the mean we computed earlier. We subtract off the mean and square the result.
After we compute that column of (x-M)^2 values, we add them up to get what is shown in the highlighted yellow cell at the bottom of the column.
That sum is approximately 0.04403076924
Next, we divide that over n-1 = 13-1 = 12
0.04403076924 /12 = 0.00366923077
That is the sample variance. Apply the square root to this to get the sample standard deviation. This is the point estimate of the population standard deviation. As the name implies, it works for samples that estimate population parameters.
sqrt(0.00366923077) = 0.06057417576822
This rounds to 0.061 which is the final answer.
Find the missing side lengths leave your answer as a racials simplest form
Solve each equation.
1)-9 + x = 4
Simplify 4^-4.
please help I have 10 minutes
Answer:
1/256
Step-by-step explanation:
[tex]4^{-4}[/tex]
[tex](1/4)^{4}[/tex]
=> 1/256
William sold tooth pick for €2 a pack.On Selling 60% of his ware he still had 200 left.How much money did he collect from his entire sales?
Answer:
.......................
Please show detailed work if possible-that will help me to better understand the questions
start with this expression:
f(x) = 2x2 − x − 10
1st- What are the x-intercepts of the graph of f(x)? Show work on how to get this
2nd- Is the vertex of the graph of f(x) going to be a maximum or minimum? What are the coordinates of the vertex? Show work on how to get this
Part C: What are the steps you would use to graph f(x)? show how you can use the answers obtained in Part A and Part B to draw a graph
Answer:
We are given the function:
[tex]f(x)=2x^2-x-10[/tex]
[tex]Here,\\a=2, b=-1,c=-10[/tex]
1. X-intercepts are the points at which the graph of a function intersects or cuts the x-axis. Since the x-intercept always lies on the x-axis, its ordinate or y-coordinate will always be 0. Since the function is quadratic, it will have at most 2 x-intercepts.
In order to find the x intercept, we basically solve for x at y=0:
[tex]f(x)=2x^2-x-10\\As\ y=0,\\0=2x^2-x-10\\2x^2-x-10=0\\ 2x^2-5x+4x-10=0\\x(2x-5)+2(2x-5)=0\\(x+2)(2x-5)=0\\Hence,\\Individually:\\x=-2,\ x=\frac{5}{2}[/tex]
Hence, the x-intercepts of the parabola of f(x) is (-2,0),(2.5,0)
2. The vertex of parabola is determined as maximum or minimum, solely on how it opens. This depends on the nature of the co-efficient of the x^2 term or 'a'. If a is positive the parabola opens upwards (minimum point) and downwards (maximum point) if negative. Hence, here as a=2, the parabola opens upwards and its vertex is minimum.
[tex]Vertex=(\frac{-b}{2a},\frac{-D}{4a})\\Hence,\\D=b^2-4ac\\Substituting\ a=2,b=-1,c=-10:\\D=(-1)^2-4*2*-10=1+80=81\\Hence,\\Vertex\ of\ f(x)=(\frac{-(-1)}{2*2},\frac{-81}{4*2})=(\frac{1}{4},\frac{-81}{8})[/tex]
3. [Please refer to the attachment]
From the graph, we observe that the parabola cuts the x-axis at (-2,0),(2.5,0). Also, its clear that the axis of symmetry passes through [tex](\frac{1}{4},\frac{-81}{8})[/tex], which is its minimum point.
Answer:
A chord of a circle is 9cm long if it's distance from the centre of the circle is 5cm calculate the radius of the circle
Assume the population of regulation basketball weights are normally distributed with a mean of 22 and a standard deviation of 1 ounce. If a sample of 100 regulation basketballs is taken, what is the probability that its sample mean will be greater than 22.2 ounces
Answer: 0.0228
Step-by-step explanation:
please check photo explanation
The probability that the sample mean will be greater than 22.2 ounces will be equal to 0.0228
What is probability?Probability is calculated as the proportion of favorable events to all potential scenarios of an event. The proportion of positive results, or x, for an experiment with 'n' outcomes can be expressed.
As per the given values in the question,
[tex]\mu_x[/tex] = 22
σ(x) = σ/√n
= 1/√100
σ(x) = 0.1
P(x>22.2) = 1- P(x<22.2)
= 1- P(x × μ(x))/ σ(x) < (22.2 - 22)/0.1
1 - P (z < 2.00)
1- 0.9772
= 0.0228
To know more about probability:
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f (x) = sqrt(x)+ 2, g(x)=x^2+ 1
find f(g(x))
and g(f(x))
Answer:
[tex]f(x) = \sqrt{x} + 2 \\ \\ g(x) = {x}^{2} + 1 \\ \\ f{g(x)} = \sqrt{ {x}^{2} + 1 } + 2 \\ \\ g{f(x)} = {( \sqrt{x} + 2 )}^{2} + 1[/tex]
If a $6 per unit tax is introduced in this market, then the new equilibrium quantity will be
Answer:
soory i dont know just report me if you angry
whats the scale factor of this one please?????
Answer:
0.5
Step-by-step explanation:
E to E'
(0, 3) to (0, 1.5) each term of E' is ½ of the corresponding term of E
N to N'
(-1, 1) to (-0.5, 0.5) each term of N' is ½ of the corresponding term of N
U to U'
(2, -2) to (1, -1) each term of U' is ½ of the corresponding term of U
V to V'
(1, -3) to (0.5, -1.5) each term of V' is ½ of the corresponding term of V
can someone explain step by step what to do next? I am trying to find the vertex, focus, and directrix of this parabola.
y=2x^2
y=2x^2 im using this equation (x-h)^2=4p(y-k)
y/2=x^2
this is my problem I dont know where to put y/2 in the equation I am using
Answer:
Hey hi how are you can you be my friend please..Step-by-step explanation:
And can you give me a fever can you please just marks me as brainliests please..Answer:
Step-by-step explanation:
Parabola: y=2x²
Let say (a,b) the focus and y=k the directrix.
[tex]formula\ to\ use:\ \boxed{y=\dfrac{(x-a)^2}{2(b-k)} +\dfrac{b+k}{2} }\\\\\left \{\begin {array}{ccc}a&=&0\\2&=&\dfrac{1}{2(b-k)} \\\dfrac{b+k}{2} &=&0\\\end {array} \right.\\\\\\\left \{\begin {array}{ccc}a&=&0\\b-k&=&\dfrac{1}{4} \\b+k &=&0\\\end {array} \right.\\\\\\\left \{\begin {array}{ccc}a&=&0\\b&=&\dfrac{1}{8} \\k &=&\dfrac{-1}{8} \\\end {array} \right.\\\\\\focus=(0,\dfrac{1}{8} )\\\\directrix:\ y=\dfrac{-1}{8}[/tex]
Which of the following statements accurately describes the period of a trigonometric function?
Answer:
b
Step-by-step explanation:
b is correct.
Five hundred randomly selected adult residents in Sacramento are surveyed to determine whether they believe children should have limited smartphone access. Of the 500 people surveyed, 381 responded yes - they believe children should have limited smartphone access.
You wish to estimate a population mean y with a known population standard devi- ation o = 3.5. If you want the error bound E of a 95% confidence interval to be less than 0.001, how large must the sample size n be?
Answer:
The sample size must be of 47,059,600.
Step-by-step explanation:
We have to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1 - 0.95}{2} = 0.025[/tex]
Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].
That is z with a p-value of [tex]1 - 0.025 = 0.975[/tex], so Z = 1.96.
Now, find the margin of error M as such
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
Standard deviation:
[tex]\sigma = 3.5[/tex]
If you want the error bound E of a 95% confidence interval to be less than 0.001, how large must the sample size n be?
This is n for which M = 0.001. So
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
[tex]0.001 = 1.96\frac{3.5}{\sqrt{n}}[/tex]
[tex]0.001\sqrt{n} = 1.96*3.5[/tex]
[tex]\sqrt{n} = \frac{1.96*3.5}{0.001}[/tex]
[tex](\sqrt{n})^2 = (\frac{1.96*3.5}{0.001})^2[/tex]
[tex]n = 47059600[/tex]
The sample size must be of 47,059,600.
What is the quotient of the synthetic division problem below, written in
polynomial form?
5)2 1 -55
O A. -2x+11
O B. -2x+9
O C. 2x+11
O D. 2x+9
Answer:
C. 2x+11
Step-by-step explanation:
2x+11≈21 -55
2x+11≈21 -55
2x+11≈21 -55
2x+11≈21 -55
2x+11≈21 -55
The initial population of the town was estimated to be 12,500 in 2005. The population has increased by about 5.4% per year since 2005.
Formulate the equation that gives the population, A(x) , of the town x years since 2005. If necessary, round your answer to the nearest thousandth.
A(x)=__(_)^x
Answer:
[tex]A(x) = 12500(1.054)^x[/tex]
Step-by-step explanation:
Exponential equation for population growth:
Considering a constant growth rate, the population, in x years after 2005, is given by:
[tex]A(x) = A(0)(1 + r)^x[/tex]
In which A(0) is the population in 2005 and r is the growth rate, as a decimal.
The initial population of the town was estimated to be 12,500 in 2005.
This means that [tex]A(0) = 12500[/tex]
The population has increased by about 5.4% per year since 2005.
This means that [tex]r = 0.054[/tex]
So
[tex]A(x) = A(0)(1 + r)^x[/tex]
[tex]A(x) = 12500(1 + 0.054)^x[/tex]
[tex]A(x) = 12500(1.054)^x[/tex]
What is the x intercept of the graph that is shown below? Please help me
Answer:
(-2,0)
Step-by-step explanation:
The x intercept is the value when it crosses the x axis ( the y value is zero)
x = -2 and y =0
(-2,0)
Write the coefficient of x².
A coefficient is a numerical value that is multiplied with a variable.
Coefficient of x² is -3For a certain country, the bar graph shows the population of it’s public school students, in millions, and the amount that the country’s government spent on public education, in billions of dollars, for five selected years. Complete part A and B.
A.
Express 2007 student population in scientific notation. (Use the multiplication symbol as needed)
B.
Express the amount that the government spent on public education in 2007 in scientific notation. (Use the multiplication symbol as needed)
Answer:
B
Step-by-step explanation:
I took a test in school and this was the answer...at least for my class.
help me plzzzzzzzzzzzzzzzzzzzzzzzzzz
The cost of producing pens with the company logo printed on them consists of a onetime setup fee of $265.00 plus $0.95 for each pen produced. This cost can be calculated using the formula C=265.00+0.95p, where p represents the number of pens produced and C is the cost. Use the formula to calculate the cost of producing 2900 pens.
Choose the system of inequalities that best matches the graph below. A. B. C. D.
The system of inequalities that is graphed is:
y ≤ - (2/3)*x
y < x - 3
So the correct option is B.
Which system of inequalities is the graphed one?First, we can see that for both of the inequalities the shaded part is below the lines.
You also can see that the solid line (correspondent to the symbol ≤) is the one with a negative slope, and the dashed line (correspondent with the line <) is the one with a positive slope.
Only with that, we conclude that the correct option is B.
y ≤ - (2/3)*x
y < x - 3
If you want to learn more about inequalities:
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PLEASE HELP AND BE RIGHT PLEASE AND THANK YOU
Answer:
4 units
Step-by-step explanation:
A'B' = 2 × AB
8 = 2×AB
AB = 8/2 = 4
Answer:
16 units
Step-by-step explanation:
The triangle will get bigger because it has a scale factor that is greater than 1.
k=scale factor
k<1=reduction
k>1=enlargement
NO LINKS OR ANSWERING QUESTIONS YOU DON'T KNOW!!!
1. How can a matrix be used to solve a system of equations? Demonstrate by solving the following system. Show your work. In other words, use a problem of system of equations problem as an example.
Answer:
Step-by-step explanation:
Assuming the system is solvable in the first place, create an augmented matrix of coefficients from the equations. Then put the matrix into reduced row echelon form.
Example is attached.
"Demonstrate by solving the following system."
You need to provide the system of equations.
The perimeter of a rectangle is 202 the length is 26 more than 4 times the width find the dimensions
Answer:
Width = xLength = 26 + 4xPerimeter
[tex]202 = x + x + 26 + 4x + 26 + 4x\\202-26-26=10x\\150=10x\\x=15[/tex]
Therefore, the dimensions are
Width = x = 15Length = 26 + 4x = 26 + 4(15) = 86The length of two sides of triangular field are 16 m and 19m . The perimeter of rectangle is 50 cm find the third side?
50 - (16 + 19)
= 50 - 35
= 15m
Will give brainliest
A tablet at a local electronics store is in high demand and will only be available to customers for a limited time. The store initially has 4 cases of the tablet on hand. The store manager receives new supplies of the tablet each week. At the beginning of week 1, the store manager receives an additional order from the distributor of 5 cases of tablets. At the beginning of week 6, the manager receives another order of 10 cases. Which of the following equations best models the scenario for how many cases of the tablet the store can expect to receive each week?
a. y=4
b. y=x+4
c. y=-6x
Drag the tiles to the correct boxes to complete the pairs.
Given that x= 3 + 81 and y= 7 - 1 match the equivalent expressions.
-15 + 19
58 + 106
-&
411
-29 - 531
I. 2y
-
y
–50 ty
23 - 3y
9514 1404 393
Answer:
58 +106i-29 -53i-8 -41i-15 +19iStep-by-step explanation:
For the purpose of selecting the appropriate tile, it is only necessary to figure the real part of the sum or product.
We notice that the second product (-xy) is -1/2 times the first product (2xy). This can let you find the answers on that basis alone. The only tiles with a (-1) : (2) relationship are (-29 -53i) : (58 +106i).
__
The sum -5x +y has a real part of -5(3) +7 = -8.
The sum 2x -3y has a real part of 2(3) -3(7) = 6 -21 = -15.
Hence the sequence of answers needed on the right side is as shown above.
_____
Additional comment
You know that arithmetic operations with complex numbers (multiplication and addition) are identical to those operations performed on any polynomials. That is, "i" can be treated as a variable. The simplification comes at the end, where any instances of i² can be replaced by -1.
xy = (3 +8i)(7 -i) = 3·7 -3·i +8·7·i -8·i·i = 21 +53i -8i²
= (21 +8) +53i . . . . replaced i² with -1, so -8i² = +8
= 29 +53i
