?
What is the equation of a parabola whose focus is (-4, -1)
and whose directrix is
y = -5?
x²
y = + x – 1
8
o
y = -
x²
--X+1
8
y?
x =
+ у - 1
8
y2
X = -
8 Y+1
Answer:
1st option,
y = x²/8 + x - 1
Answered by GAUTHMATH
A certain test preparation course is designed to help students improve their scores on the LSAT exam. A mock exam is given at the beginning and end of the course to determine the effectiveness of the course. The following measurements are the net change in 6 students' scores on the exam after completing the course: 6,16,19,12,15,14.
Using these data, construct a 90% confidence interval for the average net change in a student's score after completing the course. Assume the population is approximately normal. Find the critical value that should be used in constructing the confidence interval.
Answer:
The critical value is [tex]T_c = 2.5706[/tex].
The 90% confidence interval for the average net change in a student's score after completing the course is (9.04, 18.30).
Step-by-step explanation:
Before building the confidence interval, we need to find the sample mean and the sample standard deviation:
Sample mean:
[tex]\overline{x} = \frac{6+16+19+12+15+14}{6} = 13.67[/tex]
Sample standard deviation:
[tex]s = \sqrt{\frac{(6-13.67)^2+(16-13.67)^2+(19-13.67)^2+(12-13.67)^2+(15-13.67)^2+(14-13.67)^2}{5}} = 4.4121[/tex]
Confidence interval:
We have the standard deviation for the sample, so the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 6 - 1 = 5
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 5 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.5706, that is, the critical value is [tex]T_c = 2.5706[/tex]
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.5706\frac{4.4121}{\sqrt{6}} = 4.63[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 13.67 - 4.63 = 9.04.
The upper end of the interval is the sample mean added to M. So it is 13.67 + 4.63 = 18.30.
The 90% confidence interval for the average net change in a student's score after completing the course is (9.04, 18.30).
If you get a raise from $12 per hour to $15 per hour, what is the percent change?
Answer:
25%
Step-by-step explanation:
Formula to calculate the percent change :-
Change in distance from $12 per hour to $15 per hours = 15-12=3 per hour
Previous value = $12 per hour
Now, the percent change will be :_
Hence, the percent change for from $12 per hour to $15 per hour= 25%
(I copied this answer from JeanaShupp from question-11653373 [no links])
Help me please and thank you
Step-by-step explanation:
jlejej
are u using chrome os
Please help!
The quantities x and y are proportional.
x: 4 5 10
y: 10 12.5 25
Find the constant of proportionality (r) in the equation y=rx.
9514 1404 393
Answer:
r = 2.5
Step-by-step explanation:
The constant of proportionality can be found by solving the equation for r:
r = y/x
Then any corresponding values of x and y can be used to find r:
r = 25/10 = 2.5
The constant of proportionality is 2.5.
[tex]\sqrt{-25[/tex]
Answer:
±5i
Step-by-step explanation:
sqrt(-25)
We know that sqrt(ab) = sqrt(a) sqrt(b)
sqrt(-1) sqrt(25)
±i 5
±5i
Find the standard deviation for the following group of data items.
9, 11, 11, 16
The standard deviation for the given data items is 2.6
The standard deviation of the given data items can be calculated by taking the square root of the variance.
Variance is a measure of variability and it is calculated by taking the average of squared deviations from the mean.
Hence, we will first determine the mean of the given data items.
Mean is simply the average of the numbers.
Therefore mean of the given data items is
[tex]Mean = \frac{9+11+11+16}{4}[/tex]
[tex]Mean = \frac{47}{4}[/tex]
Mean = 11.75
Now, for the variance of the data
[tex]Variance = \frac{(9-11.75)^{2}+(11-11.75)^{2}+(11-11.75)^{2}+(16-11.75)^{2} }{4}[/tex]
[tex]Variance = \frac{(-2.75)^{2}+(-0.75)^{2}+(-0.75)^{2}+(4.25)^{2} }{4}[/tex]
[tex]Variance = \frac{7.5625+0.5625+0.5625+18.0625}{4}[/tex]
[tex]Variance = \frac{26.75}{4}\\[/tex]
∴ Variance = 6.6875
But,
Standard deviation [tex]= \sqrt{Varinace}[/tex]
∴Standard deviation [tex]=\sqrt{6.6875}[/tex]
Standard deviation = 2.586
Standard deviation ≅ 2.6
Hence, the standard deviation for the given data items is 2.6
Learn more on standard deviation here: https://brainly.com/question/18562832
What do these have in common
Answer:
All Equal to 0
Step-by-step explanation:
0 = 0
3 - 3 = 0
0/4 = 0
12 - 3*4 = 0
Will mercury with a density of 13.6 g/mL float or sink?
Mercury will sink
(sorry if Im wrong)
Answer:
Sink.
Step-by-step explanation:
Mercury is a quicksilver and hence will sink.
How many times greater is
6.6 x 10^10
than
3 x 10^7
2.2
22
1000
2200
Answer:
2,200
Step-by-step explanation:
6.6 x 10^10
= 66,000,000,000
3 x 10^7
= 30,000,000
66,000,000,000 ÷ 30,000,000
2,200
Answer:
2200.
Step-by-step explanation:
6.6 / 3 * 10^10/10^7
= 2.2 * 10^3
= 2200
Prove that: sec⁴B - sec²B = tan⁴B + tan²B.
Step-by-step explanation:
sec⁴B - sec²B = sec²B(sec²B - 1)
= (1 + tan²B)(tan²B)
= tan⁴B + tan²B
= Right-hand side (Proven)
What percentage of area is above the mean on a normal curve?
Group of answer choices
34%
68%
97.35%
50%
Answer:
z=0
50%
Step-by-step explanation:
Solve for y. 14y-6(y-3)=22
Answer:
y=0.5
Step-by-step explanation:
14y-6(y-3)=22
14y-6y+18=22
8y+18=22
8y=4
y=0.5
Then we check our work...
14(0.5)-6((0.5)-3)=22
7-6(-2.5)=22
7+15=22
7+15 does equal 22, so this solution is correct.
A number has ........... number of factors but ........... number of multiple.
A number has fixed number of factors but infinite number of multiples
Ex:-
Take a number 12
It has factors 1,2,3,4,6,12
It is fixed.
But
It has multiples 12,24,36,48,60...
It is infinite
Find the missing segment in the image below
I need help with C,D,E,F,G thank you
Answer:
D = 120 Degrees , E : x = 14 , F: <JHK = 21, G: Summplementary Angle is 96 Degrees
Step-by-step explanation:
4X+2X = 180
6X=180
X=30
<ABD = 4X = 4(30) = 120
Read the image for instructions
Answer:
4 ther are 4 line symmetery
Answer:
two lines of symmetry
(a vertical and a horizontal)
Books, and then you have 44+45x=?
Answer:
45x=-44
x=-44/45
Step-by-step explanation:
is this a free question?
1. In the past, Sam cashed his paycheck each month at Ready Cash, a check cashing service that
charges a 5% fee. He recently opened a checking account at Bank of America so he can now
deposit and/or cash his paycheck without a fee. If Sam is making $28,500 per year, how much will
he save by not going to Ready Cash anymore?
Step-by-step explanation:
28000 ÷ 100
=280
280 × 5
=1400
Is 3.6 a real number
A random number generator is used to create a list of 300 single digit numbers
a 800g boulder has a density of 8g/cm^3. What is the volume of the boulder?
Answer:
Below
Step-by-step explanation:
You can use this formula to calculate the volume of an object
Volume = Mass / Density
Plugging everything in...
Volume = 800g / 8 g/cm^3
= 100 cm^3
Hope this helps!
The volume of the boulder will be equal to 100 cubic centimeters.
What are volume and density?A substance's density is defined as its mass per unit volume. The density in other words can be defined as the ratio of mass and volume. Its unit will be kg per cubic meter.
The volume is defined as the space occupied by an object in three-dimensional geometry.
It is given that an 800g boulder has a density of 8g/cm^3. The volume will be calculated by using the formula below:-
Volume = Mass / Density
Volume = 800g / 8 g/cm^3
= 100 cm^3
Therefore, the volume of the boulder will be equal to 100 cubic centimeters.
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The volume of a rectangular prism (shown below) is 48x^3+56x^2+16x Answer the following questions:
(1) What are the dimensions of the prism?
(2) If x = 2, use the polynomial 48x^3+56x^2+16x to find the volume of the prism.
(3) If x = 2, use the factors found in part a to calculate each dimension.
(4) Using the dimensions found in part c, calculate the volume. Show all work.
Answer:
(a)
[tex]Length = 8x\\Width = 3x + 2\\Height = 2x + 1[/tex]
(b)
[tex]P(2) = 640[/tex]
(c)
[tex]Length= 16[/tex]
[tex]Width = 8[/tex]
[tex]Height =5[/tex]
(d)
[tex]Volume = 640[/tex]
Step-by-step explanation:
Given
[tex]P(x) = 48x^3 + 56x^2 + 16x[/tex]
Solving (a): The prism dimension
We have:
[tex]P(x) = 48x^3 + 56x^2 + 16x[/tex]
Factor out 8x
[tex]P(x) = 8x(6x^2 + 7x + 2)[/tex]
Expand 7x
[tex]P(x) = 8x(6x^2 + 4x + 3x + 2)[/tex]
Factorize
[tex]P(x) = 8x(2x(3x + 2) +1( 3x + 2))[/tex]
Factor out 3x + 2
[tex]P(x) = 8x(3x + 2)(2x + 1)[/tex]
So, the dimensions are:
[tex]Length = 8x\\Width = 3x + 2\\Height = 2x + 1[/tex]
Solving (b): The volume when [tex]x = 2[/tex]
We have:
[tex]P(x) = 48x^3 + 56x^2 + 16x[/tex]
[tex]P(2) = 48 * 2^3 + 56 * 2^2 + 16 * 2[/tex]
[tex]P(2) = 640[/tex]
Solving (c): The dimensions when [tex]x = 2[/tex]
We have:
[tex]Length = 8x\\Width = 3x + 2\\Height = 2x + 1[/tex]
Substitute 2 for x
[tex]Length=8*2[/tex]
[tex]Length= 16[/tex]
[tex]Width = 3*2+2[/tex]
[tex]Width = 8[/tex]
[tex]Height = 2*2 + 1[/tex]
[tex]Height =5[/tex]
So, we have:
[tex]Length= 16[/tex]
[tex]Width = 8[/tex]
[tex]Height =5[/tex]
Solving (d), the volume in (c)
We have:
[tex]Volume = Length * Width * Height[/tex]
[tex]Volume = 16 * 8 * 5[/tex]
[tex]Volume = 640[/tex]
Find the value of x.
A. 57
B. 72
C. 90
D. 124
Answer:
90
Step-by-step explanation:
Angle Formed by Two Chords= 1/2(SUM of Intercepted Arcs)
105 = 1/2 (120+x)
210 = 120+x
Subtract 120 from each side
210-120 = x
90 =x
The value of Intercepted Arcs x will be 90. so option C is correct.
What is the relation between line perpendicular to chord from the center of circle?If the considered circle has center O and chord AB, then if there is perpendicular from O to AB at point C, then that point C is bisecting(dividing in two equal parts) the line segment AB.
Or
|AC| = |CB|
Angle Formed by Two Chords= 1/2 (Sum of Intercepted Arcs)
105 = 1/2 (120+x)
210 = 120+x
Subtract 120 from each side;
210-120 = x
90 =x
Hence, the value of Intercepted Arcs x will be 90. so option C is correct.
Learn more about chord of a circle here:
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simplify 27-{ 9+(12-5)÷4} with solution
Answer:
16.25
Step-by-step explanation:
first do 12 -5 = 7. then 7/4 = 1.75 then 9+1.75 = 10.75 and finally 27-10.75= 16.25
If the area of a circle is 16π, the circumference of the circle is:
A. 8π
B. 16π
C. 2π
D. 4π
Hi! I'd appreciate if you could help me on this question.
Liam is buying bottles of soda in packages that contain 8 bottles each. If the total number of sodas Liam bough t was between 45 and 50, how many did he buy? Explain your answer.
Answer:
48
Step-by-step explanation:
We need to find the multiples of 8
8,16,24,32,40,48
48 is between 45 and 50 so he must have bought 48
Answer:
6 bottles
Step-by-step explanation:
For this question we need to know the multiple of 8 which are:
8 x 1 = 8
8 x 2 = 16
8 x 3 = 24
8 x 4 = 32
8 x 5 = 40
8 x 6 = 48
8 x 7 = 56
There is only one multiple, which is greater than 45 but less than 50, which is 8x6 l.
This means he bought 6 bottles.
Answered by g a u t h m a t h
PLS HELP
Find an equation of the line with a y-intercept of -3 and an x-intercept of -4.5
Answer:
y = - [tex]\frac{2}{3}[/tex] x - 3
Step-by-step explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Calculate m using the slope formula
m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]
with (x₁, y₁ ) = (0, - 3) and (x₂, y₂ ) = (- 4.5, 0 ) ← coordinates of intercepts
m = [tex]\frac{0-(-3)}{-4.5-0}[/tex] = [tex]\frac{0+3}{-4.5-0}[/tex] = [tex]\frac{3}{-4.5}[/tex] = - [tex]\frac{2}{3}[/tex]
The line crosses the y- axis at (0, - 3 ) ⇒ c = - 3
y = - [tex]\frac{2}{3}[/tex] x - 3 ← equation of line
I need the answer explained
Answer:
1.33
Step-by-step explanation:
62 can only be subtracted from 82 once. So 82.46-62 would be 20.46. Since you can't subtract anymore you put a decimal point. 62x3=186 and 20.46-186=1.86 and you can subtract 186-186=0.
If 40 men working on a U.S. government project can complete the job in 100 hours, how many men would be required to complete the job in 80 hours?
Answer:50
Step-by-step explanation:(40x100):80
Answer: 50 workers
Let the ratio be
(40×100):80
= 400/80
= 50
Therefore 50 workers will complete the same work in 80 hours.
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