Answer:
z = - .5
Step-by-step explanation:
z = (x - μ)/ σ
z = 56 - 60/8 = -.5
In a large midwestern university (the class of entering freshmen being on the order of 6000 or more students), an SRS of 100 entering freshmen in 1999 found that 20 finished in the bottom third of their high school class. Admission standards at the university were tightened in 1995. In 2001 an SRS of 100 entering freshmen found that 10 finished in the bottom third of their high school class. The proportion of all entering freshmen in 1999 and 2001, who graduated in the bottom third of their high school class, are p1 and p2, respectively.Is there evidence that the proportion of freshmen who graduated in the bottom third of their high school class in 2001 has been reduced, as a result of the tougher admission standards adopted in 2000, compared to the proportion in 1999? To determine this, you test the hypothesesH0 : p1 = p2 , Ha : p1 > p2.The P-value of your test isA. 0.976.B. 0.024.C. 0.048.D. 0.001.
Answer:
B. 0.024
The p-value of the test is 0.024 < 0.05(standard significance level), which means that there is enough 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 testing the hypothesis, 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:
Of 100, 20 were in the bottom thid. So
[tex]p_B = \frac{20}{100} = 0.2[/tex]
[tex]s_B = \sqrt{\frac{0.2*0.8}{100}} = 0.04[/tex]
2001:
Of 100, 10 were in the bottom third, so:
[tex]p_A = \frac{10}{100} = 0.1[/tex]
[tex]s_A = \sqrt{\frac{0.1*0.9}{100}} = 0.03[/tex]
To determine this, you test the hypotheses H0 : p1 = p2 , Ha : p1 > p2.
Can also be rewritten as:
[tex]H_0: p_B - p_A = 0[/tex]
[tex]H_1: p_B - p_A > 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 sample:
[tex]X = p_B - p_A = 0.2 - 0.1 = 0.1[/tex]
[tex]s_A = \sqrt{s_A^2+s_B^2} = \sqrt{0.03^2+0.04^2} = 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 proportions of at least 0.1, which is 1 subtracted by the p-value of z = 2.
Looking at the z-table, z = 2 has a p-value of 0.976.
1 - 0.976 = 0.024, so the p-value is given by option B.
The p-value of the test is 0.024 < 0.05(standard significance level), which means that there is enough evidence that the proportion of freshmen who graduated in the bottom third of their high school class in 2001 has been reduced.
what is the answer to 7b-7-8b= -15
Answer:
b=8
Step-by-step explanation:
7b-7-8b=-15
Combine like terms
-b-7=-15
Add 7 on both sides
-b=-15+7
-b=-8
Divide by -1
b = 8
Answer: b = 8
Step-by-step explanation:
Given
7b - 7 - 8b = -15
Combine like terms
-b - 7 = -15
Add 7 on both sides
-b - 7 + 7 = -15 + 7
-b = -8
Divide -1 on both sides
-b / -1 = -8 / -1
b = 8
Hope this helps!! :)
Please let me know if you have any questions
HELP ASAP ILL GIVE BRAINLIST
In a study on the placebo effect on 100 students, 64 were found to perform better on tests after taking a fake pill to improve concentration. What is the experimental probability the placebo pill induced better concentration on the student exams?
Answer:
16/25 or 64%
Step-by-step explanation:
In this problem we see that 64 out of the 100 students did better on the exams. So, to find the answer we must find the percentage form of 64 out of 100.
Step one:
what exactly is 64 out of 100? Well, in the math world when we see 'out of' we know that means 'divided by'. So, 64 out of 100 is 64/100.
Step two:
now we have to turn 64/100 into a percentage. We know that 1/100 is 1% so lets multiply 1 by 64. 64*1 = 64. This means that 64/100 = 64%.
I'm not 100% sure what form you need your answer in but if you need it in percentage for the answer is 64%. If you need your answer in a fraction form the answer would be 64/100 or 16/25 if we simplify the answer.
I hope this helps!!
I'll give brainliest :)
Are the lines y = –x – 4 and 5x + 5y = 20 perpendicular? Explain.
Yes; the product of their slopes is −1.
Yes; their slopes are equal.
No; their slopes are equal.
No; their slopes are not equal
Answer:
C
Step-by-step explanation:
In the equation y = -x - 4, the gradient is -1.
While in the second equation,
5x + 5y = 20
y = -x + 4
So the gradient is -1 too
Both sides are not perpendicular to each other because if you apply the formula, m1m2 = -1, and if substitute both gradient, (-1)(-1) = 1 ≠ -1
Therefore, no they are not perpendicular but parallel instead.
Answer: C
Step-by-step explanation:
Look above fool
enter the repeating digit
[tex] \frac{9}{11} [/tex]
Answer:
Step-by-step explanation:
[tex]\frac{9}{11}=0 .818181....[/tex]
__
= 0.81
Can someone please help me?
Answer:
The equation of the perpendicular line (PR) to line PQ is; y = -0.5x - 1.5
Step-by-step explanation:
The line is perpendicular to line adjoined by points P(-3,0) and Q(0,6)
The slope of line PQ is;
Slope = change in y ÷ change in x = [tex]\frac{6 - 0}{0 -- 3}[/tex] = 2
The product of slopes of two perpendicular lines = -1
Hence the slope of line PR = -1 ÷ slope of line PQ = -1/2
Taking another point (x,y) and point P(-3,0) the equation of line PR is;
Slope = [tex]\frac{y - 0}{x - -3} = -\frac{1}{2}[/tex]
Cross-multiplying gives;
2y = -x - 3 , y = -x/2 - 3/2 , y = -0.5x - 1.5
If I have 180$ and a pack of dvds cost 18 how much can I buy
Answer:
10 packs of dvds
Step-by-step explanation:
$180 / $18 = 10 packs
You can buy a maximum of 10 dvd packs
Answer:
you can buy 10 dvds that is thr answer
Select the correct answer. Consider this system of equations, where function f is quadratic and function g is linear:
y = f(x)
y = g(x)
Which statement describes the number of possible solutions to the system?
A. The system may have no, 1, 2, or infinite solutions.
B. The system may have no, 1, or infinite solutions.
C. The system may have 1 or 2 solutions.
D. The system may have no, 1, or 2 solutions
Answer:
C is the answer
Step-by-step explanation:
Quadratic equations have at most 2 solution, and linear equations only have 1 solution, and since y is equal to both of them, it can only have 1 or 2 solutions.
The correct answer is option D. The system may have no, 1, or 2 solutions
What is quadratic equation?A quadratic equation is a second-order polynomial equation in a single variable x , ax²+bx+c=0. with a ≠ 0 .
f(x) is a quadratic function and g(x) is linear function
y=f(x)
y=g(x)
Quadratic equations have at most 2 solution
linear equations only have 1 solution,
f(x)=g(x)=y
y is equal to both of them, it can only have 1 or 2 solutions.
A line and a parabola can intersect zero, one, or two times
Therefore, a linear and quadratic system can have zero, one, or two solutions
Hence, the correct answer is option D. The system may have no, 1, or 2 solutions
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points V W X Y and Z are collinear, VZ= 52, XZ =20, and WX=XY=YZ find the indicated length
21.) WX 22.) VW 23.) WY 24.) VX 25.) WZ 26.) VY
Answer:
WX=10; VW=22; WY=20; VX=32; WZ=30;VY=42
Step-by-step explanation:
1)WX=XY=XZ/2=20/2=10
2)VW=VZ-WX-XY-YZ=VZ-3*WX=52-3*10=52-30=22
3)WY=WX+XY=2*WX=2*10=20
4)VX=VW+WX=22+10=32
5)WZ=WX+XY+YZ=3*WX=3*10=30
6)VY=VZ-YZ=52-10=42
The points V, W, X, Y and Z are collinear. The indicated lengths are
[tex]WX=10\\VW=22\\WY=20\\VX=32\\WZ=30\\VY=42[/tex]
Given :
points V, W, X, Y and Z are collinear, VZ= 52, XZ =20, and WX=XY=YZ
Lets make diagram using the given information
The diagram is attached below
XY=YZ
XZ=20, so [tex]XY+YZ=20\\Both XY and YZ are same\\XY+XY=20\\2XY=20\\Divide \; by \; 2\\XY=10[/tex]
[tex]WX=XY=YZ \\XY=10\\WY=10\\YZ=10\\[/tex]
Now we find out VW
[tex]VW+WX+XY+YZ=52\\VW+10+10+10=52\\VW+30=52\\Subtract \; 30\\VW=52-30\\VW=22[/tex]
Now we find the indicated length
[tex]WX =10[/tex]
[tex]VW=22\\WY=WX+XY=10+10=20\\VX=VW+WX=22+10=32\\WZ=WX+XY+YZ=10+10+10=30\\VY=VW+WX+XY=22+10+10=42[/tex]
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Simplify the following, leaving your answer with a positive exponent:
x^-12/ x^-7
Answer:
[tex]\frac{1}{x^{5} }[/tex]
Step-by-step explanation:
x^-12/ x^-7
= x^(-12-(-7))
= x^-5
= 1/x^5
Correct answer gets 5 stars and brainliest
Answer:
Does the answer help you?
Answer:
D
Step-by-step explanation:
Using the converse of Pythagoras' identity.
If the square of the longest side is equal to the sum of the squares on the other two sides then the triangle is right.
longest side = 12 and 12² = 144
5² + 8² = 25 + 64 = 89
Since 5² + 8² ≠ 12² , then triangle is not right → D
Two friends are writing practice problems to study for a trigonometry test. Sam writes the following problem for his friend Anna to solve:
In right triangle ABC, the measure of angle C is 90 degrees, and the length of side c is 8 inches.
Solve the triangle.
Anna tells Sam that the triangle cannot be solved. Sam says that she is wrong.
Who is right? Explain your thinking
Answer:
Anna is right in her meaning concerning on triangle solvability.
Step-by-step explanation:
The side [tex]c[/tex] represents the hypotenuse of a right triangle as [tex]C = 90^{\circ}[/tex] and is opposite to that angle. There are two ways to solve this triangle trigonometrically:
i) Law of Sine
[tex]\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}[/tex] (1)
ii) Law of Cosine
[tex]c^{2} = a^{2} + b^{2} - 2\cdot a\cdot b \cdot \cos C[/tex] (2)
The Pythagorean Theorem is a particular case of the Law of Cosine for [tex]C = 90^{\circ}[/tex]
The triangle cannot be solved as there is an input missing, either another side or another angle. If [tex]C = 90^{\circ}[/tex], then (2) is reduced into this form:
[tex]c^{2} = a^{2}+b^{2}[/tex] (2b)
In this case we need to know the measure of either [tex]a[/tex] or [tex]b[/tex] to determine its counterpart and the values of the missing angles by (1). In nutshell, Anna is right.
Consider this equation. tan) 19 17 If 8 is an angle in quadrant II, what is the value of Cos() OA. 19 6 OB. 17 6 O c. V18 6 OD. 17
Using trigonometric identities, it is found that the value of [tex]\cos{\theta}[/tex] is given by:
B. [tex]\cos{\theta} = \frac{\sqrt{17}}{6}[/tex]
What is the tangent of an angle?It is given by the division of it's sine by it's cosine, that is:
[tex]\tan{\theta} = \frac{\sin{\theta}}{\cos{\theta}}[/tex]
In this problem, the equation given is:
[tex]\tan{\theta} = -\sqrt{\frac{19}{17}}[/tex]
That is:
[tex]\frac{\sin{\theta}}{\cos{\theta}} = -\sqrt{\frac{19}{17}}[/tex]
[tex]\sin{\theta} = -\sqrt{\frac{19}{17}}\cos{\theta}[/tex]
The following identity is applied:
[tex]\sin^2{\theta} + \cos^2{\theta} = 1[/tex]
Then:
[tex]\left(-\sqrt{\frac{19}{17}}\cos{\theta}\right)^2 + \cos^2{\theta} = 1[/tex]
[tex]\frac{36}{17}\cos^2{\theta} = 1[/tex]
[tex]\cos^2{\theta} = \frac{17}{36}[/tex]
[tex]\cos{\theta} = \frac{\sqrt{17}}{6}[/tex]
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Answer:
Hi sorry I just wanted to ask is it B or D? positive or negative?
Step-by-step explanation:
edmentum is the worst
Can you please answer this answer with a step by step explanation?
the BEST answer gets the BRAINLIEST answer mark!
Answer:
Step-by-step explanation:
If K is square number, then exponents in number N are even.
Determine the period.
Answer:
4
Step-by-step explanation:
The period is the length of one cycle.
By cycle, I mean the smallest piece that can be traced and copied over and over to form the whole graph. If you notice the graph starts at x=0 and the curve makes a complete cycle by x=4. The cycle starts over again at x=4 and ends at x=8. I hope you are seeing the graph looks exactly the same from x=0 to x=4 as x=4 to x=8.
The length of one cycle of this graph is 4.
The period of function is,
P = 4
Since, In order to find the period of a graph in general, first, find the period of the parent function, and divide that by the absolute value of the coefficient of the independent variable.
Here, Graph of function is shown.
Hence, The period of function is,
P = 4
Therefore, The period of function is,
P = 4
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Algunos granos de maíz al ser calentados revientan y pierden agua de manera explosiva.
En promedio se puede considerar que tienen una masa de 125 mg y cuando explotan (palomitas
de maíz) su masa es de 106 mg. ¿Cuántos granos de maíz pira se requerirán para obtener una
libra de palomitas de maíz?
Answer:
Step-by-step explanation:
4280 granos de maíz pira se requerirán para obtener una libra de palomitas de maíz.
CálculoDado que algunos granos de maíz al ser calentados revientan y pierden agua de manera explosiva, y en promedio se puede considerar que tienen una masa de 125 mg y cuando explotan (palomitas de maíz) su masa es de 106 mg, para determinar cuántos granos de maíz pira se requerirán para obtener una libra de palomitas de maíz se debe realizar el siguiente cálculo:
453592 mg = 1 lb453592 / 106 = X4279.16 = XPor lo tanto, 4280 granos de maíz pira se requerirán para obtener una libra de palomitas de maíz.
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Sam ordered 2 tons of crushed stone. How many pounds of crushed stone does she have?
Answer:
4000
Step-by-step explanation:
1 ton = 2000 pounds
2 tons = ? pounds
Multiply:
2000 × 2 = 4000
There will be 4000 pounds of crushed stone.
Hope this helped.
Sam ordered 2 tons of crushed stone. How many pounds of crushed stone does she have?
S O L U T I O N :Here, we need to convert the tons into pounds to get the desired result
✪ According to the question :
We know that,
1 ton = 2000 pounds
2 tons = 2(1000 pounds) = 2000 pounds
Hence, she have 2000 pounds of crushed stoneplease help asap it's important!!!
Answer:
486cm^2
Step-by-step explanation:
Surface area of cube = (6a^2)
6×9×9=486.
Jeremy is making a trail mix containing raisins and peanuts. Raisins cost $1.50 per pound. Peanuts cost $2.50 per pound. Jeremy spends $10.50 to make 5 pounds of trail mix. He uses the table below to organize this information. A Table titled Trail Mix showing Pounds, Cost, and Total. The first row shows Raisins, with r, 150, and 1.5 r. The second row shows Peanuts, with 5 minus r, 2.50, and 2.5 left-parenthesis 5 minus r right parenthesis. The last row shows Mixture, with 5, blank, and 10.50. Which equation can Jeremy use to determine the amount of raisins in the trail mix? r + 1.50 = 1.5r r + (5 – r) = 5 1.5r + 2.5(5 – r) = 10.50 1.5r + 2.5(5 – r) = 5
Answer:
The answer us Option C
Step-by-step explanation:
Hope this helps!!
Answer:
C
Step-by-step explanation:
ASAPPPPPPPPPPPPPPPPPPPPPPP P P P P P P P P P P P P P P P P P P P P
Answer:
5 trees per day
Step-by-step explanation:
Answer:
5 trees per day
Step-by-step explanation:
(1, 5)
(2,10)
the day increases by 1 and the trees increase by 5
The two cones below are similar. What is the value of x?
Cone 1
Height = 10
Radius = 3
Cone 2
Height = 3
Radius = x
A. 0.3
B. 0.9
C. 0.09
D. 0.18
Answer:
If they are similar, the ratio of 10/3 should be the same as the 3/x
then solve
10/3 = 3/x
cross multiply
10x=8
x = 9/10
so C. is the right answer
The missing value in the smaller cone is 0.9 units.
What is similarity?Similarity in math is a concept that relates to the shape and size of figures. Two figures are similar if they have the same shape, but not necessarily the same size.
Given that, two similar cones, we need to find the value of x in the smaller cone,
Since, the cones are similar, then according to the definition of similarity,
we know that the dimensions will be in equal proportion,
Let the dimensions of the big cone be H (height) and R (radius) and that of smaller cone be h (height) and r (radius)
So,
H / R = h / r
10 / 3 = 3 / x
x = 9/10
x = 0.9
Hence, the missing value in the smaller cone is 0.9 units.
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Two points, A and B, are on opposite sides of a building. A surveyor chooses a third point, C, 80 yd from B and 104 yd from A, with angle ACB
measuring 51.2º. How far apart are A and B (to the nearest yard)?
HURRYYY GIVING 20 POINTS!!
Answer:
Step-by-step explanation:
The law of cosine helps us to know the third side of a triangle when two sides of the triangle are already known the angle opposite to the third side is given. The distance between A and B is 85.6 yds.
What is the Law of Cosine?The law of cosine helps us to know the third side of a triangle when two sides of the triangle are already known the angle opposite to the third side is given. It is given by the formula,
[tex]c =\sqrt{a^2 + b^2 -2ab\cdot Cos\theta}[/tex]
where
c is the third side of the triangle
a and b are the other two sides of the triangle,
and θ is the angle opposite to the third side, therefore, opposite to side c.
The three points A, B, and C will form a triangle. Therefore, using the law of cosine the measure of the third side AB can be written as,
[tex]AB =\sqrt{(AC)^2 + (BC)^2 -2(AC)(BC)\cdot \cos(51.2^o)}\\\\AB =\sqrt{(80)^2 + (104)^2 -2(80)(104)\cdot \cos(51.2^o)}\\\\AB = \sqrt{6400+10816-16640\cos51.2^o}\\\\AB = \sqrt{7328.4}\\\\AB=85.6\rm\ yd[/tex]
Hence, the distance between A and B is 85.6 yds.
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Demonstrate on the whiteboard how to find the center and radius of a circle using an equation.
Answer:
Step-by-step explanation:
Equation for a circle of radius r, centered at (h,k):
(x-h)² + (y-k)² = r²
9. What is the area of the given triangle? Round to the nearest tenth. (1 point) A 7 cm 38° B 13 cm C Area = cm2
Answer:
Area = 13.5 cm^2
Step-by-step explanation:
When we know 2 sides and the included angle
the area is =(½)ab sin C
where a and b are the side lengths and C is the angle between them
Area = 1/2 ( 13*7) sin 38
Area = 13.48477
Rounding to the nearest tenth
Area = 13.5 cm^2
A vehicle is travelling from rest. After 10 seconds its velocity will be 20ms find acceleration?
Initial velocity (u) = 0m/s
Final velocity (v) = 20m/s
Time (t) = 10 s
Acceleration (a)
= (v - u)/t
= [(20m/s) - (0m/s)]/10s
= (20m/s)/10s
= (20m/s²)/10
=> 2m/s²
Please help with this question
Answer:
-3.662rad × 180/π = -209.8°
Step-by-step explanation:
Answer:
1 degree = .01745329 radians
1 radian = 57.2957877856 degrees
-209.8 degrees = .01745329 * -209.8 =
-3.66170024200 radians
Step-by-step explanation:
The population of a place in a particular year increased by 15% next year it decreased by 15%. Find the net increase or decrease percent in the initial population
Answer:
there was a decrease of 2.25%
Step-by-step explanation:
Let me illustrate with an example
Assume the population is 100
percentage increase = 100 + 15 = 115% = 1.15%
Population after 15% increase = 100 x 1.15 = 115
Percentage decrease = 100 - 15 = 85% = 0.85
Population after 15% decreases 115 x 0.85 = 97.75
rate of increase = (97.75 / 100) - 1 = -2.25%
The output of a relation is the difference of three times the input and five. Select the correct answer from each drop-down menu. The equation that represents this relation is . The relation a function. If the domain of the relation is x > 2, the range of the relation is y > .
Answer:
The equation that represents this relation is [tex]y = 3x - 5[/tex].
The relation is a function.
If the domain of the relation is x > 2, the range of the relation is [tex]y >1[/tex]
Step-by-step explanation:
Given
Output = 3 * Input - 5
Required
Complete the gap
Solving (a):The equation for the relation.
Let
[tex]x \to[/tex] input
[tex]y \to[/tex] output
The relation is:
[tex]y = 3 * x - 5[/tex]
[tex]y = 3x - 5[/tex]
Solving (b): Is the relation, a function?
Yes; Because every value of x has a distinct value in 7
Solving (c): The range:
Domain: [tex]x > 2[/tex]
Substitute 2 for x in [tex]y = 3x - 5[/tex]
[tex]y =3 * 2 - 5[/tex]
[tex]y =6 - 5[/tex]
[tex]y =1[/tex]
The range is:
[tex]y >1[/tex]
Answer:
The equation that represents this relation is [ y= 3x - 5 ]
The relation [ is ] a function.
If the domain of the relation is x > 2, the range of the relation is y > [ 1 ].
Step-by-step explanation:
The output, y, of a relation, is the difference of three times the input, or 3x, and 5. So, y = 3x − 5.
Substituting any x-value from the domain into the equation will result in exactly one value of y, so the relation is a function.
To find the range of the relation, given the domain, substitute the boundary point of the domain into the function equation:
When x = 2, y = 3(2) − 5 = 6 − 5 = 1.
Because substituting values of x that are greater than 2 will result in values of y that are greater than 1, the range of the relation is y > 1.
Hope this helps !!
a car can complete journey of 300 km with the average speed of 60 km per hour how long does it take to complete the journey what is the speed of the car if it covers only 200 km in the same interval of the time
please I need help urgent
Answer:
a. 5 hours
b. 40 kph
Step-by-step explanation:
300 km ÷ 60 km = 5 hours
200 km ÷ 5 hours = 40 kilometers per hour
Instructions: Find the value of the trigonometric ratio. Make sure to
simplify the fraction if needed.
Х
40
32
N
24
Y
Tan Z
Answer:
tan Z = 4/3
Step-by-step explanation:
Since this is a right triangle, we can use trig functions
tan theta= opp / adj
tan Z = 32/24
Divide top and bottom by 8
tan Z = 4/3
