Answer:
The 95% confidence interval for the true difference between the mean amounts of time spent exercising each week by people who work out in the morning and those who work out in the afternoon or evening at the three health centers is (0.5, 0.9).
Step-by-step explanation:
Before building the confidence intervals, 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.
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.
In the morning:
Sample of 57, mean of 5.2, standard deviation of 0.6, so:
[tex]\mu_1 = 5.2[/tex]
[tex]s_1 = \frac{0.6}{\sqrt{57}} = 0.0795[/tex]
In the afternoon/evening:
Sample of 70, mean of 4.5, standard deviation of 0.4, so:
[tex]\mu_2 = 4.5[/tex]
[tex]s_2 = \frac{0.2}{\sqrt{70}} = 0.0239[/tex]
Distribution of the difference:
[tex]\mu = \mu_1 - \mu_2 = 5.2 - 4.5 = 0.7[/tex]
[tex]s = \sqrt{s_1^2+s_2^2} = \sqrt{0.0795^2 + 0.0239^2} = 0.083[/tex]
Confidence interval:
The confidence interval is:
[tex]\mu \pm zs[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
95% confidence level
So [tex]\alpha = 0.05[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].
The lower bound of the interval is:
[tex]\mu - zs = 0.7 - 1.96*0.083 = 0.5[/tex]
The upper bound of the interval is:
[tex]\mu + zs = 0.7 + 1.96*0.083 = 0.9[/tex]
The 95% confidence interval for the true difference between the mean amounts of time spent exercising each week by people who work out in the morning and those who work out in the afternoon or evening at the three health centers is (0.5, 0.9).
Find the length represented by x for each pair of similar triangles.
18cm, 9cm, and x
30cm, 15cm, and 25cm
Answer:
15 cm
Step-by-step explanation:
Since the traingles are similar, we can find the ratio between the side lengths, and it will be the same for each side.
We can use the side length 9 and 15 to find this ratio. 15/9=5/3. So, the ratio of a side length of the larger triangle to the smaller one is 5/3, so our equation becomes 5/3 = 25/x. Use any method you like to find that x=15.
Hope this helped,
~cloud
Find the sum of ∑4/k=1 (-4k)
Answer:
Hello,
Answer C: -40
Step-by-step explanation:
[tex]\displaystyle \sum_{k=1}^4\ (-4k)\\\\=-4*\sum_{k=1}^4\ k\\\\=-4*4*\dfrac{1+4}{2} \\\\=-4*5*2\\\\=-40\\[/tex]
Need help plz + will give brainlest
Thanks in advance
Answer:
it is D.
Step-by-step explanation:
Find the value of each determinant
Answer:
−4304
Step-by-step explanation:
1. The given determinant is :
[tex]\begin{vmatrix}7 &31 \\ 142& 14\end{vmatrix}[/tex]
We need to find its determinant . It can be solved as follows :
[tex]\begin{vmatrix}7 &31 \\ 142& 14\end{vmatrix}=7(14)-142(31)\\\\=-4304[/tex]
So, the value of determinant is equal to −4304.
Answer:
A= -4269
B= 1768
C= 647.36
Step-by-step explanation:
A bookkeeper needs to post the cost of the desk and the chair into his records. The cost of the desk is fives times the cost if the chair. The total cost of the desk and the chair is $720, what is the cost of the chair?
Answer:
120
Step-by-step explanation:
720÷6
why?
becoz 6= 1+5
1 is the cosy of the chair
5 is the cost of the desk
if 25 liters of milk can make 8 tin of cheese how many liters of milk would b needed to make 11 tin of cheese?
Answer:
Step-by-step explanation:
34.375 Liters of milk make 11 tins of cheese. Assuming that milk is available in whole liters only, 35 Liters of milk are needed.
In a class of 70 pupils, 36 like tasty time , 34 like ice-
cream, 6 like both tasty time }
draw a Venn diagram to show the data.
find how
many
like neither tasty time nor ice-cream
Step-by-step explanation:
I think this might be the correct answer
The number of pupils that like neither tasty-time nor ice cream is 6 if in a class of 70 pupils, 36 like tasty time, 34 like ice cream, 6 like both tasty times.
What is the Venn diagram?It is defined as the diagram that shows a logical relation between sets.
The Venn diagram consists of circles to show the logical relation.
We have:
In a class of 70 pupils, 36 like tasty time, 34 like ice cream, 6 like both tasty time.
Total = 70 pupils
Number of like tasty time = 36
Number of like ice cream = 34
Number of like both = 6
Let x be the total number of pupils that like neither tasty-time nor ice cream
The number of pupils that like ice cream only = 34 - 6 = 28
The number of pupils that like tasty-time only = 36 - 6 = 30
From the Venn diagram:
28 + 30 + 6 + x = 70
x = 70 - 64
x = 6
Thus, the number of pupils that like neither tasty-time nor ice cream is 6 if in a class of 70 pupils, 36 like tasty time, 34 like ice cream, 6 like both tasty times.
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1.) Three numbers form a geometric sequence whose common ratio is 0.5. If the first is reduced to 10 more than one quarter its value, the second decreased by 10, and the third increased by 10 more than twice its value, the resulting three numbers form an arithmetic sequence. Determine the original three numbers.
Let x be the first number in the sequence, so the first three numbers are
{x, 0.5x, 0.5²x}
Then
{x/4 + 10, 0.5x - 10, 2(0.5²x) + 10}
is arithmetic, so there is some constant c such that
0.5x - 10 = x/4 + 10 + c ==> x/2 - 10 = x/4 + 10 + c
2(0.5²x) + 10 = 0.5x - 10 + c ==> x/2 + 10 = x/2 - 10 + c
Solve the second equation for c :
x/2 + 10 = x/2 - 10 + c
c = 20
Substitute this into the first equation and solve for x :
x/2 - 10 = x/4 + 10 + 20
x/4 = 40
x = 160
Then the terms are
{160, 80, 40}
Find the missing side or angle.
Round to the nearest tenth.
b=15 a=30 c=29 a=[?]. Acellus plz
Answer:
∠ A ≈ 79.0°
Step-by-step explanation:
Using the Cosine rule to find the angle
cosA = [tex]\frac{b^2+c^2-a^2}{2bc}[/tex]
= [tex]\frac{15^2+29^2-30^2}{2(15)(29)}[/tex]
= [tex]\frac{225+841-900}{870}[/tex]
= [tex]\frac{166}{870}[/tex] , then
A = [tex]cos^{-1}[/tex] ([tex]\frac{166}{870}[/tex] ) ≈ 79.0° ( to the nearest tenth )
Which matrix equation represents the system of equations?
{-x+ 2y = 0
y= -2
We are given a system of equations,
[tex]\begin{cases}-x+2y=0\\y=-2\\ \end{cases}[/tex]
This will translate into a 2x2 matrix of coefficients (because 2 equations and 2 unknowns),
[tex]\begin{bmatrix}-1&2\\0&1\\ \end{bmatrix}[/tex]
The matrix will then be applied to the vector (lower dimensions on top),
[tex]\begin{bmatrix}x\\y\\ \end{bmatrix}[/tex]
And the result vector will be whats on the other side of equals sign,
[tex]\begin{bmatrix}0\\-2\\ \end{bmatrix}[/tex]
So to put everything together,
[tex]\begin{bmatrix}-1&2\\0&1\\ \end{bmatrix}\begin{bmatrix}x\\y\\ \end{bmatrix}=\begin{bmatrix}0\\-2\\ \end{bmatrix}[/tex]
Hope this helps :)
How many 4-digit passcodes can be created if each digit can be any number, 0-9?
6,561
10,000
40
5,040
Answer:
6,561
that's a good number
0 thru 9 is 10 numbers.
Each digit can be 1 of 10 numbers:
Total combinations = 10 x 10 x 10 x 10 = 10,000
Answer: 10,000
write your answer in simplest radical form
Answer:
n = 8√2
Step-by-step explanation:
From the question given above, the following data were obtained:
Angle θ = 60°
Opposite = 4√6
Hypothenus = n =?
The value of n can be obtained by using the sine ratio as illustrated below:
Sine θ = Opposite / Hypothenus
Sine 60 = 4√6 / n
√3/2 = 4√6 / n
Cross multiply
n × √3 = 2 × 4√6
n × √3 = 8√6
Divide both side by √3
n = 8√6 / √3
Rationalise
n = 8√6 / √3 × (√3/√3)
n = 8√(6×3) / 3
n = 8√18 / 3
Recall
√18 = √(9×2) = √9 × √2 = 3√2
Thus,
n = 8√18 / 3
n = 8 × 3√2 / 3
n = 8√2
You are dealt one card from a 52-card deck. Find the probability that you are not dealt a heart.
The probability is ___.
(Type an integer or a fraction. Simplify your answer.)
Answer:
3/4
Step-by-step explanation:
There are 13 hearts in a 52 deck.
52-13=39
39/52=3/4
The probability that you are not dealt a heart from the deck of cards is 3/4.
What is the probability that you are not dealth with a heart?Probability determines the chances that an event would occur. The probability the event occurs is 1 and the probability that the event does not occur is 0.
The probability that you are not dealth with a heart = 1 - (number of hearts / total number of cards)
1 - 13/52 = 39/52 = 3/4
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Complete the equation describing how x
and y are related.
х у
y = [ ? ]x
-2
-1
0
1
2
3
-6
-3
0
3
6
9
Enter the answer that
belongs in [?]
Answer:
y=3x
Step-by-step explanation:
-6/-2=3, -3/-1=3, 3/1=3. 6/2=3
how many cubic meters of gravel are in the back of a full dump truck that measures 7m wide by 4m tall by 16m long
Answer:
Step-by-step explanation:
Assuming the gravel reaches the top of the walls and no higher, the volume is 7×4×16 = 448 m³
Answer:
hello thereee
now vol of truck = l b h = 7 * 4 * 16 = 448 m^3
( 448m^3 is final ans...
glad for brainliest.... hope that helps <3
Form a polynomial whose zeros and degree are given,
Zeros: - 2, 2,7; degree: 3
Type a polynomial with integer coefficients and a leaning coefficient of 1 in the box below.
F(x)=
Answer:
if the zeros are x = -2, x = 0, and x = 1
then (x + 2), x and (x - 1) are factors of the polynomial
multiply these factors together
p(x) = x(x + 2)(x - 1)
p(x) = x(x2 + x - 2)
p(x) = x3 + x2 - 2x
this is a polynomial of degree 3 with the given roots
An exponential function f(x) = ab^xpasses through the points (0, 2) and (3, 54). What are the values of a and
b?
a=
b =
Answers:
a = 2
b = 3
=======================================================
Explanation:
Plug in x = 0 and y = 2 to find that
y = a*b^x
2 = a*b^0
2 = a*1
2 = a
a = 2
Then plug in x = 3 and y = 54 to determine the value of b
y = a*b^x
y = 2*b^x
54 = 2*b^3
2b^3 = 54
b^3 = 54/2
b^3 = 27
b = (27)^(1/3)
b = 3
So we have y = a*b^x update to y = 2*3^x
2. About how much is 123.1 do you weigh in pounds? Estimate if you don't know☺ Find an online converter and find out how many kilograms that is.
Answer:
123.1 pounds is vary long, and I don't want to repeat, so 55.8372207 repeat.
Step-by-step explanation:
If you have any questions regarding my answer, tell me them in the comments, and I will come answer them for you. Have a good day.
4) If the perimeter of a square is 48cm",
What is the length of each side?
Simplify your answer.
Answer:
If the total perimeter of square is 48 cm, then the length of one side is equal to 48 divided by 4, since all sides of a square are the same.
So, the correct answer is 12.
Let me know if this helps!
The length of each side is 12cm.
Explanation:
The perimeter of a square is calculated by the formula:
P = 4a , where P = perimeter, and a = length of any side, all sides being equal in a square.
From the given data we write:
48 = 4a
Divide both sides by
4.12 = a
The length of each side is 12cm.
A hunter walks 400m Up a hill which slopes at an angle of 20 to the horizontal. Calculate,correct to the nearest metre, the: a. horizontal distance he covered b.vertical height through which he rises.
let y be the horizontal distance and x the vertical
y/400 = cos 20
y=400 cos20
y=376m
x/400 =sin20
x=400sin20
x=137m
An article is marked to sell at a gain of 10%. If it be sold for Rs. 7.50 less there would be loss of 5%, find the cost price.
Answer:
750,. is answer
I hope it helps
Help very confusing to me???!
Answer:
Heyy mate... here's ur ans ;)
they asked us to apply pythagarus theorem becoz that theorem proves
that it is rectangle so lets get started
( p - perpendicular / b - base / h - hypotenuse )
a) =>
B = 8.1 m
P = 6.3 m
H = 10.15m
Now applying thm => H^2=p^2+b^2
(8.1)^2 + (6.3)^2 = (10.15)^2
65.61 + 39.69 = 103.02
so now LHS = 105.3 and RHS = 103.02 hence
LHS not equal to RHS
so is not rectangle
b) =>
B = 14.4
P = 5.2
H = 15.31
Now applying thm => H^2=p^2+b^2
(5.2)^2 + (14.4)^2 = (15.31)^2
27.04 + 207.36 = 234.39
LHS = 234.4 and RHS = 234.39
just taking approximation rhs is 234.4
hence
LHS = RHS
so it is a rectangle
please mark it brainliest <3
HELLO! CAN ANYBODY PLEASE GIVE THE ANSWERS TO THESEEEE! WOULD REALLY MEAN A LOT
Ron has 22 coins with a total value of $ 1.85. The coins are nickels (5 cents) and dimes (10 cents). How many of each coin does he have?
Please help asap and thank you in advance!!
Answer:
18 dimes and 1 nickle
Step-by-step explanation:
This is because 18 time 10 is 180 and one of 5 add it and this is $1.85
Remeber a dollar is 100 cents
Derive the equation of the parabola with a focus at (2,4) and a directrix of y=8
Answer:
The equation of the parabola with a focus at (2,4) and a directrix of y=8 is,
48-8y=(x-2)²
What is the remainder when (2x^3 + 4x^2 – 32x + 18) = (x + 3)?
Answer:
X= -5.3 & Y= -2.34
X= 0.49 & Y= 3.49
X= 2.85 & Y=5.85
Step-by-step explanation:
To find the intersection you would need to graph it and locate where both lines will intersect.
find the missing length indicated
============================================================
Explanation:
Let y be the length of the vertical dashed red line in the drawing. More specifically, this dashed line is an altitude.
Along the top, the entire segment is 400 units long. The right piece is 144 units long, so the left piece is 400-144 = 256 units long.
The triangles are similar, allowing us to set up a proportion like so:
144/y = y/256
144*256 = y*y
36864 = y^2
y^2 = 36864
y = sqrt(36864)
y = 192
So this is the length of that vertical dashed red line.
--------------------------------
Now shift your attention solely on the smaller triangle on the right side. It is a right triangle with legs 144 and 192. The hypotenuse is x.
We can use the pythagorean theorem to find x.
a^2 + b^2 = c^2
c = sqrt( a^2 + b^2 )
x = sqrt( 144^2 + 192^2 )
x = 240
240.
Let y be the length of the vertical dashed red line in the drawing. More specifically, this dashed line is an altitude.
Along the top, the entire segment is 400 units long. The right piece is 144 units long, so the left piece is 400-144 = 256 units long.
The triangles are similar, allowing us to set up a proportion like so:
144/y = y/256
144*256 = y*y
36864 = y^2
y^2 = 36864
y = sqrt(36864)
y = 192
So this is the length of that vertical dashed red line.
Now shift your attention solely to the smaller triangle on the right side. It is a right triangle with legs 144 and 192. The hypotenuse is x.
We can use the Pythagorean theorem to find x.
a^2 + b^2 = c^2
c = sqrt( a^2 + b^2 )
x = sqrt( 144^2 + 192^2 )
x = 240
What is Pythagorean Theorem?Pythagorean theorem, the well-known geometric theorem that the sum of the squares on the legs of a right triangle is equal to the square on the hypotenuse (the side opposite the right angle)—or, in familiar algebraic notation, a2 + b2 = c2.
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Graph y=|x|+5, how does it compare to parent graph y=|x|
9514 1404 393
Answer:
it is shifted 5 units upward
Step-by-step explanation:
The y-coordinate is a measure of the distance above the x-axis. When 5 is added to a y-coordinate, the point is shifted 5 units upward.
The function y = |x| +5 adds 5 units to the y-value of every point of the graph of y = |x|. The graph of y=|x|+5 is shifted 5 units upward from the parent graph.
Find the value of
[tex] {z}^9{ \times {z}^10 = {z}^x [/tex]
Step-by-step explanation:
Just use the Law of Indices.
"What mathematical ideas are you curious to know more about as a result of takingthis class? Give one example of a question about the material that you'd like to explorefurther, and describe why this is an interesting question to you."
One mathematical idea I've always been curious about is "integration and derivation".
Integration is about assimilating different variables. Derivation is a mathematical process whereby a result is gotten from some initial assumptions.
Integration is used everyday in different aspects of our lives. For example, if a person is travelling from let's say point A to point B, the speed used by the person might vary but through integration, one can easily get the accurate speed.
Through the division of equations into smaller bits, once can use integration to get the answer that one seeks. Architect can use integration in building the right structures at the exact places where the structures fits.
Likewise derivatives can be used by businesses in assessing whether a profit or loss will be made for a particular transaction or sale of product.
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