Distance between two points khan academy

Answer:

The p-value of the test is 0.4414, higher than the standard significance level of 0.05, which means that there is not a a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees.

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.

Apartment:

38 out of 78, so:

[tex]p_A = \frac{38}{78} = 0.4872[/tex]

[tex]s_A = \sqrt{\frac{0.4872*0.5128}{78}} = 0.0566[/tex]

Home:

46 out of 84, so:

[tex]p_H = \frac{46}{84} = 0.5476[/tex]

[tex]s_H = \sqrt{\frac{0.5476*0.4524}{84}} = 0.0543[/tex]

Test if the there a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees:

At the null hypothesis, we test if there is no difference, that is, the subtraction of the proportions is equal to 0, so:

[tex]H_0: p_A - p_H = 0[/tex]

At the alternative hypothesis, we test if there is a difference, that is, the subtraction of the proportions is different of 0, so:

[tex]H_1: p_A - p_H \neq 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 samples:

[tex]X = p_A - p_H = 0.4872 - 0.5476 = -0.0604[/tex]

[tex]s = \sqrt{s_A^2 + s_H^2} = \sqrt{0.0566^2 + 0.0543^2} = 0.0784[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{s}[/tex]

[tex]z = \frac{-0.0604 - 0}{0.0784}[/tex]

[tex]z = -0.77[/tex]

P-value of the test and decision:

The p-value of the test is the probability of the difference being of at least 0.0604, to either side, plus or minus, which is P(|z| > 0.77), given by 2 multiplied by the p-value of z = -0.77.

Looking at the z-table, z = -0.77 has a p-value of 0.2207.

2*0.2207 = 0.4414

The p-value of the test is 0.4414, higher than the standard significance level of 0.05, which means that there is not a a significant difference in the proportion of apartment dwellers and home owners who own artificial Christmas trees.

Answer:

W₂ is three times W₁ (W₂ = 3W₁)

Step-by-step explanation:

Applying,

W = ke²/2............. Equation 1

Where W = workdone in stretching the spring, k = spring constant, e = extension.

For W₁,

W₁ = ke₁²/2

Given: e₁ = 30-20 = 10 cm = 0.1 m

Substitute these value into equation 1

W₁ = k(0.1²)/2

W₁ = 0.005k Joules

For W₂,

W₂ = (ke/2)-W₁

Given: e = (40-20) = 20 cm = 0.1 m

Substitute these value into equation 1

W₂ = (k×0.2²/2)-0.005

W₂ = 0.015k Joules.

W₂/W₁ = 0.015k/0.005k

W₂/W₁ = 3

Therefore,

W₂ = 3W₁

Answer:

The original height of the plant was 2 mm

Step-by-step explanation:

Given

[tex]y = 2 + 4x[/tex]

Required

Interpret the y-intercept

The y-intercept is when [tex]x = 0[/tex]

So, we have:

[tex]y = 2 + 4 *0[/tex]

[tex]y = 2 + 0[/tex]

[tex]y = 2[/tex]

This implies that the original or initial height was 2 mm

Answer:

z(max) = 16

z(min) = -24

Step-by-step explanation:

2x - y = 12  multiply by 2

4x - 2y = 24  (1)

4x + 2y = 0  add equations

8x = 24

x = 3

4(3) + 2y = 0

y = -6

so (3, -6) is a common point on these two lines

z = 2(3) + 5(-6) = -24

4x - 2y = 24   (1)

x + 2y = 6   add equations

      5x = 30

        x = 6

6 + 2y = 6

         y = 0

so (6, 0) is a common point on these two lines

z = 2(6) + 5(0) = 12

4x + 2y = 0    multiply by -1

-4x - 2y = 0

  x + 2y = 6  add equations

       -3x = 6

         x = -2

-2 + 2y = 6

         y = 4

so (-2, 4) is a common point on these two lines

z = 2(-2) + 5(4) = 16

Complete question is;

The cost of producing x units of a particular commodity is C(x) = ⅔x² + 6x + 45 shillings and the production level t hours into a particular production run is x(t) = 0.3t² + 0.04t. At what rate is cost changing with respect to time after 5 hours?

Answer:

dC/dt = 49.45

Step-by-step explanation:

Since C(x) = ⅔x² + 6x + 45

And x(t) = 0.3t² + 0.04t

This means that;

C(x) = C(x(t))

The rate at what cost is changing with respect to time is given as;

dC/dt

Thus, from chain rule;

dC/dt = (dC/dx) × (dx/dt)

dC/dx = (4/3)x + 6

dx/dt = 0.6t + 0.04

Now, when t = 5, then;

x(5) = 0.3(5)² + 0.04(5)

x = 7.7

Thus;

dC/dx = (4/3)x + 6 = (4/3)(7.7) + 6 = 16.267

At 5 hours,

dx/dt = 0.6(5) + 0.04 = 3.04

Thus;

dC/dt = 16.267 × 3.04

dC/dt = 49.45

Answer:

Yes one should consider to buy the policy as important to have insured plan that help at the time of need.

Step-by-step explanation:

Step-by-step explanation:

0 slope means it has in x.

so the equation is y=-1, because that is the coord for the points'y axsis

Answer: 1.28571428571. This number is infinite.

Step-by-step explanation:

Answer:

1.29 rounded

Step-by-step explanation:

Answer:

$1.85 = £1

Step-by-step explanation:

55680/72.50 = 786

55680/128 = 435

435x = (786 + 19.80)

x = 805.8/435

x = 1.85

Answer:

£1 = $1.72

Step-by-step explanation:

55680/72.50=768

55680/128=435

768.00 - 19.80 = 748.20

x = 748.20 / 435

x = $1.72

Answer:

a) P(79 <= P <= 81) = 0.9968

b) P( X >  81 ) = 0.0002

Step-by-step explanation:

mean value = 75 GPa

standard deviation = 1.7 GPa

a) Determine P(79 <= P <= 81)

given that : n = 25

attached below is the detailed solution

P(79 <= P <= 81) = 0.9968

b) Determine how likely the sample mean diameter will exceed 81

given that n = 36

mean diameter = 81

P( X >  81 ) = 0.0002

Answer:

Step-by-step explanation:

Recall that the equation of a line is y = mx + b.

Excellent. Let's plug in the values we are given into the general equation for a line. We get 10 = 1/2 * 4 + b.

Simplify to 10 = 2 + b, and we get b = 8.

Our final equation, then, is y = 1/2 x + 8.

Hope this helps!

Answer:

The idea is to transform the expression by multiplying [tex](\sqrt{x + 1} - \sqrt{x})[/tex] with its conjugate, [tex](\sqrt{x + 1} + \sqrt{x})[/tex].

Step-by-step explanation:

For any real number [tex]a[/tex] and [tex]b[/tex], [tex](a + b)\, (a - b) = a^{2} - b^{2}[/tex].

The factor [tex](\sqrt{x + 1} - \sqrt{x})[/tex] is irrational. However, when multiplied with its square root conjugate [tex](\sqrt{x + 1} + \sqrt{x})[/tex], the product would become rational:

[tex]\begin{aligned} & (\sqrt{x + 1} - \sqrt{x}) \, (\sqrt{x + 1} + \sqrt{x}) \\ &= (\sqrt{x + 1})^{2} -(\sqrt{x})^{2} \\ &= (x + 1) - (x) = 1\end{aligned}[/tex].

The idea is to multiply [tex]\sqrt{x}\, (\sqrt{x + 1} - \sqrt{x})[/tex] by [tex]\displaystyle \frac{\sqrt{x + 1} + \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}[/tex] so as to make it easier to take the limit.

Since [tex]\displaystyle \frac{\sqrt{x + 1} + \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}} = 1[/tex], multiplying the expression by this fraction would not change the value of the original expression.

[tex]\begin{aligned} & \lim\limits_{x \to \infty} \sqrt{x} \, (\sqrt{x + 1} - \sqrt{x}) \\ &= \lim\limits_{x \to \infty} \left[\sqrt{x} \, (\sqrt{x + 1} - \sqrt{x})\cdot \frac{\sqrt{x + 1} + \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}\right] \\ &= \lim\limits_{x \to \infty} \frac{\sqrt{x}\, ((x + 1) - x)}{\sqrt{x + 1} + \sqrt{x}} \\ &= \lim\limits_{x \to \infty} \frac{\sqrt{x}}{\sqrt{x + 1}+ \sqrt{x}}\end{aligned}[/tex].

The order of [tex]x[/tex] in both the numerator and the denominator are now both [tex](1/2)[/tex]. Hence, dividing both the numerator and the denominator by [tex]x^{(1/2)}[/tex] (same as [tex]\sqrt{x}[/tex]) would ensure that all but the constant terms would approach [tex]0[/tex] under this limit:

[tex]\begin{aligned} & \lim\limits_{x \to \infty} \sqrt{x} \, (\sqrt{x + 1} - \sqrt{x}) \\ &= \cdots\\ &= \lim\limits_{x \to \infty} \frac{\sqrt{x}}{\sqrt{x + 1}+ \sqrt{x}} \\ &= \lim\limits_{x \to \infty} \frac{\sqrt{x} / \sqrt{x}}{(\sqrt{x + 1} / \sqrt{x}) + (\sqrt{x} / \sqrt{x})} \\ &= \lim\limits_{x \to \infty}\frac{1}{\sqrt{(x / x) + (1 / x)} + 1} \\ &= \lim\limits_{x \to \infty} \frac{1}{\sqrt{1 + (1/x)} + 1}\end{aligned}[/tex].

By continuity:

[tex]\begin{aligned} & \lim\limits_{x \to \infty} \sqrt{x} \, (\sqrt{x + 1} - \sqrt{x}) \\ &= \cdots\\ &= \lim\limits_{x \to \infty} \frac{\sqrt{x}}{\sqrt{x + 1}+ \sqrt{x}} \\ &= \cdots \\ &= \lim\limits_{x \to \infty} \frac{1}{\sqrt{1 + (1/x)} + 1} \\ &= \frac{1}{\sqrt{1 + \lim\limits_{x \to \infty}(1/x)} + 1} \\ &= \frac{1}{1 + 1} \\ &= \frac{1}{2}\end{aligned}[/tex].

Answer:

Hello,

Step-by-step explanation:

[tex]\displaystyle \lim_{x \to \infty} \sqrt{x}*(\sqrt{x+1}-\sqrt{x} ) \\\\\\= \lim_{x \to \infty}\dfrac{ \sqrt{x}*(\sqrt{x+1}-\sqrt{x} )*(\sqrt{x+1}+\sqrt{x} )}{\sqrt{x+1} +\sqrt{x} } \\\\= \lim_{x \to \infty} \dfrac{\sqrt{x} *1}{\sqrt{x+1} +\sqrt{x} } \\\\\\= \lim_{x \to \infty} \dfrac{1} {\sqrt {\dfrac {x+1} {x} }+\sqrt{\dfrac{x}{x} } } \\\\\\=\dfrac{1} {\sqrt {1}+\sqrt{1} } \\\\\\=\dfrac{1} {2} \\[/tex]

Answer:

395.52

Step-by-step explanation:

247.2/2.5=98.88(1 bib)

98.88x4=395.52(4 bibs)

Answer: [tex]10,000\ lb.ft[/tex]

Step-by-step explanation:

Given

Initial weight of the bucket is [tex]145\ lb[/tex]

It is lifted at constant rate and rate of sand escaping is [tex]0.5\ lb/ft[/tex]

At any height weight of the sand is [tex]w(h)=145-0.5h[/tex]

Work done is given by the product of applied force and displacement or the area under weight-displacement graph

from the figure area is given by

[tex]\Rightarrow W=\int_{0}^{80}\left ( 145-0.5h \right )dh\\\\\Rightarrow W=\left | 145h-\dfrac{0.5h^2}{2} \right |_0^{80}\\\\\Rightarrow W=\left [ 145\times 80-\dfrac{0.5(80))^2}{2} \right ]-0\\\\\Rightarrow W=11,600-1600\\\\\Rightarrow W=10,000\ lb.ft[/tex]

Answer:

[tex]\begin{array}{cc}{Status} & {Probability} & {1} & {0.0845} & {2} & {0.1127} & {3} & {0.1870} & {4} & {0.1927}& {5} & {0.4231} \ \end{array}[/tex]

Step-by-step explanation:

Given

The above table

Required

The discrete probability distribution

The probability of each is calculated as:

[tex]Pr = \frac{Frequency}{Total}[/tex]

Where:

[tex]Total = 2140+ 2853 + 4734 + 4880 + 10715[/tex]

[tex]Total = 25322[/tex]

So, we have:

[tex]P(1) = \frac{2140}{25322} = 0.0845[/tex]

[tex]P(2) = \frac{2853}{25322} = 0.1127[/tex]

[tex]P(3) = \frac{4734}{25322} = 0.1870[/tex]

[tex]P(4) = \frac{4880}{25322} = 0.1927[/tex]

[tex]P(5) = \frac{10715}{25322} = 0.4231[/tex]

So, the discrete probability distribution is:

[tex]\begin{array}{cc}{Status} & {Probability} & {1} & {0.0845} & {2} & {0.1127} & {3} & {0.1870} & {4} & {0.1927}& {5} & {0.4231} \ \end{array}[/tex]

Answer:

y = 3.6

x = 3.5

Step-by-step explanation:

The triangles are similar.

[tex]\frac{3}{2.4} = \frac{x}{2.8} = \frac{4.5}{y}[/tex]

Find y:

[tex]\frac{4.5}{y} = \frac{5}{4}[/tex]

[tex]4.5 * 4 = 5y => 18 = 5y => y = 3.6[/tex]

Find x:

[tex]\frac{x}{2.8} = \frac{5}{4}[/tex]

[tex]2.8 * 5 = 4x => 14 = 4x => x = 3.5[/tex]

Answer:

it should be letter c

Step-by-step explanation:

I hope this help

Answer:

Step-by-step explanation:

One way of solution is to plot the lines and points and confirm the answer visually.

See attached.

Another way is to substitute the coordinates and verify if they satisfy both of the inequalities.

Each of the methods gives us the correct answer choice of D.

Answer:

15.4 degrees

Step-by-step explanation:

b= 53

h = 55

cos -¹( 53/53)= 15.4

Answer:

A) area decreases

Step-by-step explanation:

Example: we have a 2 by 3 rectangle with area of 2*3 = 6. If we cut the first dimension in half, then we have a 1 by 3 rectangle that has area 1*3 = 3. The area has decreased. To keep the area the same, we would have to increase the other dimension some specific amount.

HOPE THIS HELPS

HAVE A GOOD DAY :)

ITS RASPUTIN002

9514 1404 393

Answer:

  3.6481 years

Step-by-step explanation:

The doubling time is not a function of the amount invested. It can be found by considering the account balance multiplier:

  2 = e^(rt) = e^(0.19t)

Taking logs, we can solve for t:

  ln(2) = 0.19t

  t = ln(2)/0.19 ≈ 3.6481431

Rounded to 4 decimal places, the doubling time is 3.6481 years, for either balance.

Answer:

B

Step-by-step explanation:

-2/3x<31/3

x>-31/2

x>-15 1/2

Answer:

x > - 15 1/2

Step-by-step explanation:

-2/3 x -10 < 1/3

Multiply each side by 3

3(-2/3 x -10 < 1/3)

-2x -30 < 1

Add 30 to each side

-2x-30+30 <1+30

-2x < 31

Divide by -2 remembering to flip the inequality

-2x/-2 > 31/-2

x > -31/2

x > - 15 1/2

Answer:

4999500

Step-by-step explanation:

first 5 = 5000000

second 5 = 500

difference = 5000000-500

Answer:

x=15, y=5

Step-by-step explanation:

x+y=20

x-y=10

Adding both equations;

(x+x) + (y-y) = 20+10

2x = 30

x = 30/2 = 15

Substitute x=15 into x+y=20

y= 20-x = 20-15= 5

[tex] - | 4 | < x < - |1| [/tex]

dunno if that's the desired form tough, but it states the same definition

The given inequality rewritten using absolute value sign​ as |-4|<x<|-1|.

Inequalities are the mathematical expressions in which both sides are not equal. In inequality, unlike in equations, we compare two values. The equal sign in between is replaced by less than (or less than or equal to), greater than (or greater than or equal to), or not equal to sign.

The given inequality is -4<x<-1.

An absolute value inequality is an expression with absolute functions as well as inequality signs.

Here, using absolute value sign​ we get

|-4|<x<|-1|

Therefore, the given inequality rewritten using absolute value sign​ as |-4|<x<|-1|.

To learn more about the inequalities visit:

https://brainly.com/question/20383699.

#SPJ2

Answer:

\I got not answer cause im da BUDDHA

But gimme brainliest squekky plssss

Answer:

y = csc(x) does not have any zero.

Step-by-step explanation:

If we have:

y = f(x)

a zero of that function would be a value x' such that:

y = f(x') = 0

Here we basically want to solve:

y = csc(x) = 0

First, remember that:

csc(x) = 1/sin(x)

now, the values of sin(x) range from -1 to 1.

So we want to solve:

1/sin(x) = 0

notice that a fraction:

a/b = 0

only if a = 0.

Then is easy to see that for our equation:

1/sin(x) = 0

The numerator is different than zero, then the equation never will be equal to zero.

Then:

y = csc(x) = 1/sin(x)

Does not have a zero.

Answer:

Pencils = 325 ; Pens = 975 ; Markers = 650

Step-by-step explanation:

Let :

Number of Pencils = x

Number of pens = y

Number of markers = z

2 times as many markers as pencils

z = 2x

3 times as many pens as pencils

y = 3x

x + y + z = 1950

Write z and y in terms of x in the equation :

x + 3x + 2x = 1950

6x = 1950

Divide both sides by 6

6x / 6 = 1950 / 6

x = 325

Number of pencils = 325

Pens = 3 * 325 = 975

Markers = 2 * 325 = 650

Pencils = 325 ; Pens = 975 ; Markers = 650