Answer:
a) The 95% confidence interval for the mean mpg, for the certain model of car is (23.3, 30.1). This means that we are 95% sure that the true mean mpg of the model of the car is between 23.3 mpg and 30.1 mpg.
b) Increasing the confidence level, the value of T would increase, thus increasing the margin of error and making the interval wider.
c) 37 cars would have to be sampled.
Step-by-step explanation:
Question a:
We have the sample standard deviation, and thus, 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 = 15 - 1 = 14
95% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 14 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 2.1448
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.1448\frac{6.2}{\sqrt{15}} = 3.4[/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 26.7 - 3.4 = 23.3 mpg.
The upper end of the interval is the sample mean added to M. So it is 26.7 + 3.4 = 30.1 mpg.
The 95% confidence interval for the mean mpg, for the certain model of car is (23.3, 30.1). This means that we are 95% sure that the true mean mpg of the model of the car is between 23.3 mpg and 30.1 mpg.
b. What would happen to the interval if you increased the confidence level from 95% to 99%? Explain
Increasing the confidence level, the value of T would increase, thus increasing the margin of error and making the interval wider.
c. The lead engineer is not happy with the interval you constructed and would like to keep the width of the whole interval to be less than 4 mpg wide. How many cars would you have to sample to create the interval the engineer is requesting?
Width is twice the margin of error, so a margin of error of 2 would be need. To solve this, we have to consider the population standard deviation as [tex]\sigma = 6.2[/tex], and then use the z-distribution.
We have that 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 pvalue 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.
How many cars would you have to sample to create the interval the engineer is requesting?
This is n for which M = 2. So
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
[tex]2 = 1.96\frac{6.2}{\sqrt{n}}[/tex]
[tex]2\sqrt{n} = 1.96*6.2[/tex]
[tex]\sqrt{n} = \frac{1.96*6.2}{2}[/tex]
[tex](\sqrt{n})^2 = (\frac{1.96*6.2}{2})^2[/tex]
[tex]n = 36.9[/tex]
Rounding up:
37 cars would have to be sampled.
Answer theas question
(1) Both equations in (a) and (b) are separable.
(a)
[tex]\dfrac xy y' = \dfrac{2y^2+1}{x+1} \implies \dfrac{\mathrm dy}{y(2y^2+1)} = \dfrac{\mathrm dx}{x(x+1)}[/tex]
Expand both sides into partial fractions.
[tex]\left(\dfrac1y - \dfrac{2y}{2y^2+1}\right)\,\mathrm dy = \left(\dfrac1x - \dfrac1{x+1}\right)\,\mathrm dx[/tex]
Integrate both sides:
[tex]\ln|y| - \dfrac12 \ln\left(2y^2+1\right) = \ln|x| - \ln|x+1| + C[/tex]
[tex]\ln\left|\dfrac y{\sqrt{2y^2+1}}\right| = \ln\left|\dfrac x{x+1}\right| + C[/tex]
[tex]\dfrac y{\sqrt{2y^2+1}} = \dfrac{Cx}{x+1}[/tex]
[tex]\boxed{\dfrac{y^2}{2y^2+1} = \dfrac{Cx^2}{(x+1)^2}}[/tex]
(You could solve for y explicitly, but that's just more work.)
(b)
[tex]e^{x+y}y' = 3x \implies e^y\,\mathrm dy = 3xe^{-x}\,\mathrm dx[/tex]
Integrate both sides:
[tex]e^y = -3e^{-x}(x+1) + C[/tex]
[tex]\ln(e^y) = \ln\left(C - 3e^{-x}(x+1)\right)[/tex]
[tex]\boxed{y = \ln\left(C - 3e^{-x}(x+1)\right)}[/tex]
(2)
(a)
[tex]y' + \sec(x)y = \cos(x)[/tex]
Multiply both sides by an integrating factor, sec(x) + tan(x) :
[tex](\sec(x)+\tan(x))y' + \sec(x) (\sec(x) + \tan(x)) y = \cos(x) (\sec(x) + \tan(x))[/tex]
[tex](\sec(x)+\tan(x))y' + (\sec^2(x) + \sec(x)\tan(x)) y = 1 + \sin(x)[/tex]
[tex]\bigg((\sec(x)+\tan(x))y\bigg)' = 1 + \sin(x)[/tex]
Integrate both sides and solve for y :
[tex](\sec(x)+\tan(x))y = x - \cos(x) + C[/tex]
[tex]y=\dfrac{x-\cos(x) + C}{\sec(x) + \tan(x)}[/tex]
[tex]\boxed{y=\dfrac{(x+C)\cos(x) - \cos^2(x)}{1+\sin(x)}}[/tex]
(b)
[tex]y' + y = \dfrac{e^x-e^{-x}}2[/tex]
(Note that the right side is also written as sinh(x).)
Multiply both sides by e ˣ :
[tex]e^x y' + e^x y = \dfrac{e^{2x}-1}2[/tex]
[tex]\left(e^xy\right)' = \dfrac{e^{2x}-1}2[/tex]
Integrate both sides and solve for y :
[tex]e^xy = \dfrac{e^{2x}-2x}4 + C[/tex]
[tex]\boxed{y=\dfrac{e^x-2xe^{-x}}4 + Ce^{-x}}[/tex]
(c) I've covered this in an earlier question of yours.
(d)
[tex]y'=\dfrac y{x+y}[/tex]
Multiply through the right side by x/x :
[tex]y' = \dfrac{\dfrac yx}{1+\dfrac yx}[/tex]
Substitute y(x) = x v(x), so that y' = xv' + v, and the DE becomes separable:
[tex]xv' + v = \dfrac{v}{1+v}[/tex]
[tex]xv' = -\dfrac{v^2}{1+v}[/tex]
[tex]\dfrac{1+v}{v^2}\,\mathrm dv = -\dfrac{\mathrm dx}x[/tex]
[tex]-\dfrac1v + \ln|v| = -\ln|x| + C[/tex]
[tex]\ln\left|\dfrac yx\right| -\dfrac xy = C - \ln|x|[/tex]
[tex]\ln|y| - \ln|x| -\dfrac xy = C - \ln|x|[/tex]
[tex]\boxed{\ln|y| -\dfrac xy = C}[/tex]
use the function to find f(-2) f(x)=[tex]3^{x}[/tex]
Answer:
[tex] \frac{1}{9} [/tex]
Step-by-step explanation:
[tex]f( - 2) = {3}^{ - 2} [/tex]
[tex]1 \div 9 = .111[/tex]
On a coordinate plane, a curved line begins at point (negative 2, negative 3), crosses the y-axis at (0, negative .25), and the x-axis at (1, 0).
What is the domain of the function on the graph?
Answer:
Option D
Step-by-step explanation:
correct answer on edge :)
Answer:
D <3
Step-by-step explanation:
Rate of change or rate of change
A farmer has 80 feet of wire mesh to surround a rectangular pen.
A) Express the area A of the pen as a function of x, also draw the figure of A indicating the admissible values of x for this problem.
B) What are the dimensions of the maximum area pen?
Answer:
Step-by-step explanation:
A). Let the dimensions of the rectangular pen are,
Length = l
Width = x
Since, farmer has the wire measuring 80 feet to surround the the pen.
Perimeter of the pen = 80 feet
2(l + x) = 80
l + x = 40
l = 40 - x ------(1)
Area of the rectangular pen = Length × width
= lx
By substituting the value of l from equation (1),
Area (A) of the pen will be modeled by the expression,
A = (40 - x)
A = 40x - x²
B). For maximum area of the pen,
Derivative of the area = 0
[tex]\frac{d}{dx}(A)=0[/tex]
[tex]\frac{d}{dx}(A)=\frac{d}{dx}(40x-x^2)[/tex]
= 40 - 2x
And (40 - 2x) = 0
x = 20
Therefore, width of the pen = 20 feet
And length of the pen = 40 - 20
= 20 feet
Dimensions of the pen should be 20 feet by 20 feet.
What number can go in the box to make the number sentence true?
6 + 0 = 10
0.
4.
6.
10.
what’s the missing side of the polygons
Answer:
the missing side is 21!!!!!!!!
A rope is 56 in length and must be cut into two pieces. If one piece must be six times as long as the other, find the length of each piece. Round your answers to the nearest inch, if necessary.
Answer:
48, 6
Step-by-step explanation:
The ratio of the pieces is 6 to 1
Add them together to get the total
6+1 = 7
Divide the total length by 7
56/7 = 8
Multiply the ratios by 8
6*8 = 48
1*8 = 6
The peices are 48 and 6
Help please guys thanks
Answer:
5
Step-by-step explanation:
(625 ^2)^(1/8)
Rewriting 625 as 5^4
(5^4 ^2)^(1/8)
We know that a^b^c = a^(b*c)
5^(4*2)^1/8
5^8 ^1/8
5^(8*1/8)
5^1
5
Answer:
[tex]5[/tex]
Step-by-step explanation:
[tex] { {(625}^{2} )}^{ \frac{1}{8} } \\ { ({25}^{2 \times 2} )}^{ \frac{1}{8} } \\ {25}^{4 \times \frac{1}{8} } \\ {5}^{2 \times 4 \times \frac{1}{8} } \\ {5}^{ \frac{8}{8} } \\ {5}^{1} \\ = 5[/tex]
i need help. i will give brainiest as soon as possible
Answer:
B
Step-by-step explanation:
Let me know if you need an explanation.
Answer:
B
Step-by-step explanation:
4x^3+x^2+5x+2
4x^3 cannot cancel with others= 4x^3
4x^2-3x^2= x^2
5x cannot cancel with others= 5x
-3+5= 2
4x^3+x^2+5x+2
Which of the following displays cannot be used to compare data from two different sets?
Answer:
Scatter plot charts are good for relationships and distributions, but pie charts should be used only for simple compositions — never for comparisons or distributions.
Tara created a 1 inch cube out of paper.
1 in
If she doubles the volume of her cube, which statement could be true?
A Tara added two inches to the height, length and width of the cube.
B Tara added two inches to the height of the cube.
C Tara doubled the measurements of the cube's height, length and width.
D Tara doubled the measurement of the cube's height.
Answer:
answer D
Step-by-step explanation:
V=L*W*H=1 ==> L=1,W=1,H=1
A:
L-> L+2=1+2=3
W -> W+2 = 1+2=3
H -> H+2=1+2=3
V=3*3*3=27 not the doubled of the volume's cube
A is false
B:
H -> H+2=1+2=3
V=1*1*3=3 not the doubled of the volume's cube
B is false
C:
H -> 2*H=2*1=2
L -> 2*L=2*1=2
W -> 2*W = 2*1=2
V=2*2*2=8 not the doubled of the volume's cube
C is false
D:
H-> H*2=1*2=2
L=1
W=1
V=1*1*2=2 is the doubled of the volume's cube
D is true
Suppose there are three balls in a box. On one of the balls is the number 1, on another is the number 2, and on the third is the number 3. You select two balls at random and without replacement from the box and note the two numbers observed. The sample space S consists of the three equally likely outcomes {(1, 2), (1, 3), (2, 3)} (disregarding order). Let X be the sum of the two balls selected. What is the mean of X
Step-by-step explanation:
a) X is a discrete uniform distribution. As the number of outcomes is only 3.
b) sum is at least 4
X ≥ 4--------
i.e (1,3) or (2,3)
probability of X ≥ 4 is 2/3
2/3= 0.667
66.7 % is the probability of the outcome to have a sum at least 4.
c) The 3 likely outcome of X
(1,2) where X ; 1+2=3
(1,3) where X ; 1+3=4
(2,3) where X ; 2+3=5
Mean = 3+4+5/ 3
Mean = 4
Feel free to ask any uncleared step
15. Find the x- and y-intercepts for the lineal equation - 3x + 4y = 24
Please explain steps! ❤️
Answer:
x (-8,0)
y (0,6)
Step-by-step explanation:
at the x-intercept, y = 0
at the y-intercept x=0
sub those values into your equation!
for the x-intercept,
-3x = 24
x = -8
for the y-intercept,
4y = 24
y = 6
which of the following is not an asymptote of the hyperbola xy = -42? y = 0 x = 0 y = x
Given:
The equation of the hyperbola is:
[tex]xy=-42[/tex]
To find:
The the equation which is not an asymptote of the hyperbola.
Solution:
We have,
[tex]xy=-42[/tex]
It can be written as:
[tex]y=\dfrac{-42}{x}[/tex]
Equating denominator and 0, we get
[tex]x=0[/tex]
So, the vertical asymptotic is [tex]x=0[/tex].
The degree of numerator is 0 and the degree of denominator is 1.
Since the degree of numerator is greater that the degree of denominator, therefore the horizontal asymptote is [tex]y=0[/tex] and there is no oblique asymptote.
Therefore, [tex]y=x[/tex] is not an asymptote of the given hyperbola and the correct option is C.
1. Consider a lottery with three possible outcomes:-$125 will be received with probability 0.2-$100 will be received with probability 0.3-$50 will be received with probability 0.5a. What is the expected value of the lottery
Answer:
The expected value of the lottery is $80
Step-by-step explanation:
To get the expected value, we have to multiply each outcome by its probability
Then we proceed to add up all of these to get the expected value of the lottery
we have this as ;;
125(0.2) + 100(0.3) + 50(0.5)
= 25 + 30 + 25 = $80
Which point is a solution to y equal greater than or less too
4x + 5?
Answer:
4x+ 4
Step-by-step explanation:
The mode of 3 numbers is 6 and the
range is 4. Write down a possible set of
numbers.
Answer:
solution,
mode of 3 numbers is 6
range is 4
possible set of numbers are
{3,4,6,{} }
Fraces bonitas para decirle a tu nv?
minimo 6
Answer:
it's. is now the MA plz I miss you
si pudiera escoger entre vivir eternamente y vivir dos veces
yo escogeria vivir dos veces porque vivir una vida eterna sin ti a mi lado seria el mayor sufrimiento, ahora vivir dos veces me dejaria tranquilo porque despues del final de mi vida podria volver a encontrarme contigo y vivir todos los momentos bellos una vez mas y eso seria un sueño volviendose realidad
Question 4 of 10
If A = (-1,-3) and B = (11,-8), what is the length of AB?
A. 12 units
B. 11 units
C. 14 units
D. 13 units
SUBMIT
Step-by-step explanation:
AB = square root of [(xA-xB)^2+(yA-yB)^2]
AB=Squarerootof(-1-11)^2 +(-3-(-8))^2=Squarerootof(-12)^2+(5)^2)
AB=Squarerootof((144)+25)= Squarerootof(169)=13 the answer is 13 units
The choice D is the right one
When a fridge is imported, a customs value of 10% must be paid for its value. If the value of the fridge after paying the customs value is rs. 55,000/-. What is the value before paying customs duty?
Answer:
55000×100/90
61,111.111
cho f(x)= sign x và g(x) = x(1-x^2). tìm f(g(x))
Answer:
[tex]f(g(x))= sign(x(1-x^{2})) = sign(x-x^{3})[/tex]
Step-by-step explanation:
Which of the following is a solution to 2sin2x+sinx-1=0?
Answer:
270 degrees
Step-by-step explanation:
If you plug in 270 in place of the x's, the function is true!
This is correct for Plate/Edmentum users!! Hope I could help :)
Which graph represents a line with a slope of -2/3 and a y-intercept equal to that of the line y=2/3x - 2
Answer: The image shown in your question as well as the one I provided is the correct answer
Step-by-step explanation:
a line with a slope of 2/3 must mean that the "m" is 2/3
y = mx + b
y = 2/3x + b
The question calls for the y-intercept to be equal to that of y=2/3x - 2
using the given equation, we easily figure out -2 is the y-intercept
so the line must go through (0,-2).
Evaluate z^2−3 z+4 , when z=−4
Answer:
8
Step-by-step explanation:
=z²-3z+4 when z is 4
=4²-3(4)+4
=16-12+4
=8
Suppose you make napkin rings by drilling holes with different diameters through two wooden balls (which also have different diameters). You discover that both napkin rings have the same height 5h. Use cylindrical shells to compute the volume V of a napkin ring of height 5 h created by drilling a hole with radius r through the center of a sphere of radius R and express the answer in terms of h .
Answer:
V = 1/6 π ( 5h)^3
Step-by-step explanation:
Height of napkin rings = 5h
Compute the volume V of a napkin ring
let a = 5
radius = r
express answer in terms of h
attached below is the detailed solution
Which expression is equivalent to 9+y+y+3
Answer:
b
Step-by-step explanation:
You only need to add the real numbers and the ys.
Answer:
12 + 2y
Step-by-step explanation:
9+y+y+3
Combine like terms
9+3 + y+y
12 + 2y
In June, an investor purchased 300 shares of Oracle (an information technology company) stock at $53 per share. In August, she purchased an additional 400 shares at $42 per share. In November, she purchased an additional 400 shares at $45. What is the weighted mean price per share? (Round your answer to 2 decimal places.)
Answer: The mean price per share is $22.91
The required weighted mean price per share is $46.09.
Given that,
In June, an investor purchased 300 shares of Oracle (an information technology company) stock at $53 per share. In August, she purchased an additional 400 shares at $42 per share. In November, she purchased an additional 400 shares at $45.
To determine the weighted mean price per share.
The average of the values is the ratio of the total sum of values to the number of values.
What is mean?The mean of the values is the ratio of the total sum of values to the number of values.
Here,
Required weight mean = 300 * 53 + 400*42 + 400 * 42 / [300 + 400 + 400]
Required weight mean = 50700/ [1100]
Required weight mean = $46.09 per share.
Thus, the required weighted mean price per share is $46.09.
Learn more about mean here:
https://brainly.com/question/15397049
#SPJ2
Ethan buys a video game on sale. If the video game usually costs $60, and it was on sale for 20% off, how much did Ethan pay? Round to the nearest whole dollar.
Ethan will pay $31.99 with the discount.
How? This is the answer because:
If 39.99 is 100%, and you are trying to find 20%...
1. you need to set it up as a ratio (of course, you do not need to do this, but it is easier for me to do it this way)
2. the ratio will look like this: 39.99/100% x/20%
3. all we need to do from here is to cross multiply!
4 39.99 x
---------- = ----------
100 20
-price is on the top and percent on the bottom
-you would now do 39.99 times 20
-then divide by 100
5. once you have 20% of 39.99, you need to subtract that answer from the total
6. 39.99 - 7.998 = 31.992 (you need to round to the nearest hundredth)
Hope this helps <3
if the two linear functions are represented two different forms the _____ is used to compare the steepness of the two functions>
Answer:
Slope
Step-by-step explanation:
Given
The above statement
Required
What compares the steep of linear functions
Literally, steepness means slope.
So, when the slope of the two linear functions are calculated, we can make comparison between the calculated slopes to determine which of the functions is steeper or less steep.
Also:
Higher slope means steeper line
e.g.
4 is steeper than 1
Game consoles: A poll surveyed 341 video gamers, and 95 of them said that they prefer playing games on a console, rather than a computer or hand-held device. An executive at a game console manufacturing company claims that the proportion of gamers who prefer consoles differs from . Does the poll provide convincing evidence that the claim is true
Answer:
proportion of gamers who prefer console does not differ from 29%
Step-by-step explanation:
Given :
n = 341 ; x = 95 ; Phat = x / n = 95/341 = 0.279
H0 : p = 0.29
H1 : p ≠ 0.29
The test statistic :
T = (phat - p) ÷ √[(p(1 - p)) / n]
T = (0.279 - 0.29) ÷ √[(0.29(1 - 0.29)) / 341]
T = (-0.011) ÷ √[(0.29 * 0.71) / 341]
T = -0.011 ÷ 0.0245725
T = - 0.4476532
Using the Pvalue calculator from test statistic score :
df = 341 - 1 = 340
Pvalue(-0.447, 340) ; two tailed = 0.654
At α = 0.01
Pvalue > α ; We fail to reject the null and conclude that there is no significant evidence that proportion of gamers who prefer console differs from 29%
