find m to cos²x-(m²-3)sinx+2m²-3=0 have root

Answers

Answer 1

Answer:

[tex]-\sqrt{2} \le m \le \sqrt{2}[/tex] would ensure that at least one real root exists for this equation when solving for [tex]x[/tex].

Step-by-step explanation:

Apply the Pythagorean identity [tex]1 - \sin^{2}(x) = \cos^{2}(x)[/tex] to replace the cosine this equation with sine:

[tex](1 - \sin^{2}(x)) - (m^2 - 3)\, \sin(x) + 2\, m^2 - 3 = 0[/tex].

Multiply both sides by [tex](-1)[/tex] to obtain:

[tex]-1 + \sin^{2}(x) + (m^2 - 3)\, \sin(x) - 2\, m^2 + 3 = 0[/tex].

[tex]\sin^{2}(x) + (m^2 - 3)\, \sin(x) - 2\, m^2 + 2 = 0[/tex].

If [tex]y = \sin(x)[/tex], then this equation would become a quadratic equation about [tex]y[/tex]:

[tex]y^{2} + (m^2 - 3)\, y + (- 2\, m^2 + 2) = 0[/tex].

[tex]a = 1[/tex].[tex]b = m^{2} - 3[/tex].[tex]c = -2\, m^{2} + 2[/tex].

However, [tex]-1 \le \sin(x) \le 1[/tex] for all real [tex]x[/tex].

Hence, the value of [tex]y[/tex] must be between [tex](-1)[/tex] and [tex]1[/tex] (inclusive) for the original equation to have a real root when solving for [tex]x[/tex].

Determinant of this quadratic equation about [tex]y[/tex]:

[tex]\begin{aligned} & b^{2} - 4\, a\, c \\ =\; & (m^{2} - 3)^{2} - 4 \cdot (-2\, m^{2} + 2) \\ =\; & m^{4} - 6\, m^{2} + 9 - (-8\, m^{2} + 8) \\ =\; & m^{4} - 6\, m^{2} + 9 + 8\, m^{2} - 8 \\ =\; & m^{4} + 2\, m^{2} + 1 \\ =\; &(m^2 + 1)^{2} \end{aligned}[/tex].

Hence, when solving for [tex]y[/tex], the roots of [tex]y^{2} + (m^2 - 3)\, y + (- 2\, m^2 + 2) = 0[/tex] in terms of [tex]m[/tex] would be:

[tex]\begin{aligned}y_1 &= \frac{-b + \sqrt{b^{2} - 4\, a\, c}}{2\, a} \\ &= \frac{-(m^{2} - 3) + \sqrt{(m^{2} + 1)^{2}}}{2} \\ &= \frac{-(m^{2} - 3) + (m^{2} + 1)}{2} = 2\end{aligned}[/tex].

[tex]\begin{aligned}y_2 &= \frac{-b - \sqrt{b^{2} - 4\, a\, c}}{2\, a} \\ &= \frac{-(m^{2} - 3) - \sqrt{(m^{2} + 1)^{2}}}{2} \\ &= \frac{-(m^{2} - 3) - (m^{2} + 1)}{2} \\ &= \frac{-2\, m^{2} + 2}{2} = -m^{2} + 1\end{aligned}[/tex].

Since [tex]y = \sin(x)[/tex], it is necessary that [tex]-1 \le y \le 1[/tex] for the original solution to have a real root when solved for [tex]x[/tex].

The first solution, [tex]y_1[/tex], does not meet the requirements. On the other hand, simplifying [tex]-1 \le y_2 \le 1[/tex], [tex]-1 \le -m^{2} + 1 \le 1[/tex] gives:

[tex]-2 \le -m^{2} \le 0[/tex].

[tex]0 \le m^{2} \le 2[/tex].

[tex]-\sqrt{2} \le m \le \sqrt{2}[/tex].

In other words,  solving [tex]y^{2} + (m^2 - 3)\, y + (- 2\, m^2 + 2) = 0[/tex] for [tex]y[/tex] would give a real root between [tex]-1 \le y \le 1[/tex] if and only if [tex]-\sqrt{2} \le m \le \sqrt{2}[/tex].

On the other hand, given that [tex]y = \sin(x)[/tex] for the [tex]x[/tex] in the original equation, solving that equation for [tex]x\![/tex] would give a real root if and only if [tex]-1 \le y \le 1[/tex].

Therefore, the original equation with [tex]x[/tex] as the unknown has a real root if and only if [tex]-\sqrt{2} \le m \le \sqrt{2}[/tex].


Related Questions

the third term and the fifth term of a geometric progression are 2 and 1/8 respectively. If all terms are positive, find the sum to the infinity of the progression​

Answers

Answer:

42 + 2/3

Step-by-step explanation:

First, to calculate the sum of an infinite geometric series, our formula is

a₁/(1-r), with a₁ being the first term of the series and r being the common ratio. Therefore, we want to find both a₁ and r.

To find r, we can first determine that 2 * r = a₄ and a₄ * r = a₅, as the ratio separates one number from the next in a geometric series. Therefore, we have

2 * r * r = a₅

2 * r² = 1/8

divide both sides by 2 to isolate the r²

r² = 1/16

square root both sides to isolate r

r =± 1/4. Note the ± because r²=1/16 regardless of whether r = 1/4 or -1/4. However, because all terms are positive, r must be positive as well, or a₄, for example, would be 2 * (-1/4) = -0.5

Therefore, r = 1/4 .

To find the first term, we know that a₁ * r = a₂, and a₂ * r = a₃. Therefore, a₁ * r² = a₃ = 2

a₁ * 1/16 = 2

divide both sides by 1/16 to isolate a₁

a₁ = 2 * 1/ (1/16)

= 2 * 16

= 32

Plugging a₁ and r into our infinite geometric series formula, we have

a₁/(1-r)

= 32  / (1-1/4)

= 32/ (3/4)

= 32/ 0.75

= 42 + 2/3

what is the volume of a cube with and edge length of 4 cm

Answers

Answer:

V = 64 cm^3

Step-by-step explanation:

Volume of a cube is given by

V = s^3 where s is the side length

V = 4^3

V = 64 cm^3

Answer:

64

Step-by-step explanation:

i guess so as the volume is 4×4×4

Match function with its corresponding graph

Answers

Answer:

Step-by-step explanation:

We can see that there are roots at (-2,0) and (-1,0)

also, the root at (-2,0) should bounce right off

and the root at (-1,0) should go through

With all that being said it has to be B

Which polynomial correctly combines the like terms and puts the given polynomial in standard form?

one-thirdx + 8x4 – two-thirdsx2 – x

8x4 – one-thirdx2 – x
8x4 + two-thirdsx2 + two-thirdsx
8x4 – two-thirdsx2 – two-thirdsx
8x4 – two-thirdsx2 – x

Answers

8x4 - two-thirdsx2 - two-thirdsx

Answer:

C

Step-by-step explanation:

I need HELP ASAP!! Please explain how to solve the problem

Answers

Answer:

[tex](x+1)^2+(y+4)^2=9\\[/tex]

Step-by-step explanation:

The general format for the equation of a circle is the following:

[tex](x-h)^2+(y-k)^2=a^2\\[/tex]

Where [tex](h,k)[/tex] is the center of the circle and ([tex]a[/tex]) is the circle's radius. Please note, that the circle ([tex](x-h)^2+(y-k)^2=a^2\\[/tex]) has a center that is (h) units to the right of the origin, and (k) units above the origin.

The given circle has a center at [tex](-1,-4)[/tex], moreover, its radius is (3) units. Therefore, one must substitute these points into the equation of a circle and simplify to find its equation:

[tex](x-h)^2+(y-k)^2=a^2\\[/tex]

[tex](x-(-1))^2+(y-(-4))^2=(3)^2\\[/tex]

[tex](x+1)^2+(y+4)^2=9\\[/tex]

Answer:

Step-by-step explanation: Let's first determine the center of the circle

which is represented by the red dot and it has the coordinates (-1, -4).

The radius of the circle is a segment that joins the center of the

circle to a point on the circle and all radii of a circle are congruent.

The radius of the circle shown here is 3.

Now, the equation of a circle is (x - h)² + (y - k)² = r² where

(h, k) is the center of the circle and r is the radius.

Now we plug all our given information into the formula.

So we have [x - (-1)]² + [y - (-4)]² = (3)².

Notice that I changed the parentheses in the formula to brackets

so that we wouldn't be dealing with too many sets of parentheses.

Changing the brackets back to parentheses,

our equation is (x + 1)² + (y + 4)² = 9.

Please help me solve this problem

Answers

Answer:

-4

they wanted you to compute using x as 3

-2*3 + 2 = -4

Step-by-step explanation:

pls help, and explain. I will give brainliest

Answers

Answer:

Nicole should take 13 1/8 cups of snack mix.

Step-by-step explanation:

If a serving size is 7/8 and Nicole wants to take 15 serving sizes (15 7/8's), then we must multiply 7/8 by 15:

15 × 7/8

Write 15 over 1 (15 = 15/1) to make the calculations easier:

15/1 × 7/8

Multiply the numerators and denominators separately:

15 × 7 / 1 × 8

105 / 8

Instructions don't say you have to do this but I will convert this improper fraction into a mixed number:

105/8 = 13 1/8

I’m struggling, if someone can explain this please

Answers

Answer:

5

Step-by-step explanation:

6*3÷√9-1

=6*3÷3-1

=6*(3/3)-1

=6*1-1

=6-1

=5

Answer:

5

Step-by-step explanation:

We already know the square root of 9 is 3 because 3 times 3 equals 9

So now the equation is 6 * 3/3 - 1

3 divided by 3 is 1

6 * 1-1

6 times 1 is 6

6-1

You should get 5

the tub started with gallons of water

Answers

Answer:

huh?

Step-by-step explanation:

reduce the following rational expression to the lowest form

[tex]\frac{64x^{5} - 64x}{( 8x^{2} +8) (2x +2) }[/tex]

please answer this. But no spam answers please
hurry

Answers

Answer:

4x(x - 1)

Step-by-step explanation:

Factor the numerator and denominator

64[tex]x^{5}[/tex] - 64x ← factor out 64x from both terms

= 64x([tex]x^{4}[/tex] - 1) ← difference of squares

= 64x(x² - 1)(x² + 1) ← x² - 1 is also a difference of squares

= 64x(x - 1)(x + 1)(x² + 1)

---------------------------------

(8x² + 8)(2x + 2) ← factor out 8 and 2 from each factor

= 8(x² + 1) × 2(x + 1)

= 16(x² + 1)(x + 1)

Then expression can be written as

[tex]\frac{64x(x-1)(x+1)(x^2+1)}{16(x^2+1)(x+1)}[/tex] ← cancel (x² + 1) and (x + 1) on numerator/ denominator

= [tex]\frac{64x(x-1)}{16}[/tex] ← cancel common factor 16 on numerator/ denominator

= 4x(x - 1)

Explain the steps necessary to convert a quadratic function in standard form to vertex form.

Answers

Step-by-step explanation:

A quadratic function in standard form is converted to vertex form by completing the square. The first two terms are used to create a perfect square trinomial after a zero pair is added. The zero pair is found by taking half of the x-term coefficient and squaring it.

arshad's father bought x sweets .(x-4)were eaten by children and 20 were left.how many sweets did his father bring

Answers

Answer:

24

Step-by-step explanation:

20+4

simple

x-4=20

x=20+4

x=24

mark me as brainliest

Answer:

24 sweets

Step-by-step explanation:

Remaining sweets = 20

x - 4 = 20

Add 4 to both sides.

x = 20 +4

x = 24

Grace bought a property valued at $200,00.00 and 20% down and a mortgage amortized over 10 years. She makes equal payments due at the end of every months. Interest on the mortgage is 4% compounded semi-annually and the mortgage is renewable after five years. a) What is the size of each monthly payment? b) What is the outstanding principal at the end of the five-year term? c) What is the cost of the mortgage for the first five years?

Answers

Answer:

Size of each monthly payment = $161.69 per month

Step-by-step explanation:

Given:

Value of property = $20,000

Downpayment = 20%

Number of payment = 12 x 10 = 120

Interest rate = 4% = 4% / 12 = 0.33 %

Computation:

Loan balance = 20,000 - 20%

Loan balance = $16,000

A] Size of each monthly payment [In Excel]

Size of each monthly payment = PMT(0.33%,120,16000,0)

Size of each monthly payment = $161.69 per month

đồ thị hàm số có bao nhiêu tiệm cận

Answers

Answer:

c

Step-by-step explanation:

U
w
R
Which angles
are adjacent?
T
S
A. RWS and UWT
B. UWT and SWR
C. UWT and TWU
D. RWS and SWT

Answers

Answer:

D. RWS and SWT

Step-by-step explanation:

Adjacent angles have a common side and a common vertex but they don't overlaps each other

The two angles that has these requirements are :

RWS and SWT

The two angles are said to be adjacent angles when they share the common vertex and side.

So , adjacent angles are :

RWS and SWT

Option D is the correct answer.

Can you help me out plz

Answers

Answer:

An isometry preserves all the following except orientation .

I have gymnastics practice very 3 days and tennis practice every 8 days. How many days will it take for me to have BOTH gymnastics and tennis practice on the same day?​

Answers

Answer:

24 days

Step-by-step explanation:

Find LCM, or least common multiple

List out all the multiples of 3:

3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ...

Now 8:

8, 16, 24, 32, 40, 48, 56, 63, 72, 80, 88...

LCM is 24, because they both hit 24 first.

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

Answer: 24 days

Explanation:

This is because 24 is the LCM (lowest common multiple) of 8 and 3.

We multiply the given values to get 8*3 = 24. This trick only works if the original two numbers have no common factors other than 1.

We can verify that 24 is indeed the LCM by listing out the multiples

multiples of 8 are: 8, 16, 24, 32, 40, ...multiples of 3 are: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ...

We see that 24 is found in both lists and it's the smallest such item. The next common item would be 48, which is a multiple of 24. In other words, every 24 days, your two practices will line up on the same day.

Give an example of when you would encounter different types of fractions in the
real world.

Answers

Step-by-step explanation:

when I had to share a bar of chocolate with 3 of my cousins....... the bar had a size of 18 cm and there were 3 of us so we divided it by 3 (18÷3) and ended up with 6, so 6cm/cousin..... ..

I'LL GIVE BRAINLIEST !!! FASTER

please explain how do you get the answer​

Answers

Answer:

84°

Step-by-step explanation:

angles in a quadrilateral add to 360°. 360-(114+76)=5x =170°. 170°/5 = 32°. x=32°

angles on a straight line add to 180°.

2x = 64°. 180-64=116°. y=116°.

y-x = 116-32 = 84°

Answer:

[tex]78[/tex]

Step-by-step explanation:

The inner angles of a quadrilateral all add up to 360. This means we can write the following

[tex]114 + 76 + 3x + 2x = 360\\190 + 5x = 360\\5x = 170\\x = 34[/tex]

Now that we have x we can find y. Notice that y and 2x are on the same line. Any line cutting another straight line will create two angles that add up to 180.

Therefore we can write

[tex]2x + y = 180\\2(34) + y = 180\\y = 112[/tex]

Finally computing y - x

[tex]y - x = 112 - 34 = 78[/tex]

The perimeter of a rectangle is 18cm . if the length is (x+2), find it's width.​

Answers

Answer:

W = 7 - x

Step-by-step explanation:

The perimeter is P= 2L + 2×W , where L is the length and W is the width.

If L = (x+2) , replacing L with the expression x+2 we have

P= 2×(X+2) + 2W ⇔ 18 = 2x + 4 + 2W ⇔ 2W =18 - 2x - 4 ⇔ 2W = 14 - 2x

⇔ W = 7 - x

A student simplified the rational expression
using the steps shown.
(x^2/5 • x^4/5 / x^2/5)^1/2 = (x^6/5/x^2/5)^1/2=(x^3)^1/2=x^3/2
Is the answer correct? Explain.

Answers

Answer:

Does the answer help you?

Answer:

[tex]\textbf{No, the answer is not correct }[/tex].

Step-by-step explanation:

The student didn't use the quotient of powers property correctly. Instead of subtracting, the student divided the exponents within the parenthesis. So, x to the two-fifths power is the correct simplified form.

[tex](\frac{x^{2/5}\times x^{4/5} }{x^{2/5} } )[/tex]

[tex]=(\frac{x^{6/5} }{x^{2/5} } )^{1/2}[/tex]

[tex]=x^{6/5-2/5} )^{1/2}[/tex]

[tex]=(x^{4/5} )^{1/2} =x^{2/5}[/tex]

OAmalOHopeO

The point B (-2, 1) has been transformed to B' (-5, -3). The transformation is described as
A T (-3,-4)
B R x=2
C T (-3,-2)
D D3

Answers

Answer:

Option A: T(-3, -4)

Step-by-step explanation:

For a general point (x, y), if we apply the transformation:

T(a, b)

at that point, the new point that we will get is:

T(a,b)[ (x, y) ] = (x + a, y + b)

Notice that if w take the difference between the new point (x + a, y + b) and the original point (x, y)

we get:

(x + a, y + b) - (x, y) = (x + a - x, y + b  y) = (a, b)

These are x-value and y-value that describe our transformation T(a, b).

Then if we know that the original point is B (-2, 1)

and the transformed point is B'( -5, -3)

We can just take the difference to get:

(-5, -3) - (-2, 1) = (-5 - (-2), -3 - 1) = (-5 + 2, -4) = (-3, -4)

Then the transformation applied is:

T(-3, -4)

The correct option is A.

What is the surface area of a cube measure 8 c/w?​

Answers

Answer:

512

Step-by-step explanation:

if 8 is the edge using the formula

V=a³=8³

V=512

Scott and Ashley each improved their yards by planting daylilies and ivy. They bought their
supplies from the same store. Scott spent $170 on 12 daylilies and 13 pots of ivy. Ashley spent
$172 on 14 daylilies and 2 pots of ivy. What is the cost of one daylily and the cost of one pot of
ivy?

Answers

Answer:

x = cost of daylily = $12

y = cost of ivy = $2

Step-by-step explanation:

Let

x = cost of daylily

y = cost of ivy

Scott:

12x + 13y = 170

Ashley:

14x + 2y = 172

12x + 13y = 170 (1)

14x + 2y = 172 (2)

Multiply (1) by 14 and (2) by 12

168x + 182y = 2380 (3)

168x + 24y = 2064 (4)

Subtract (4) from (3) to eliminate x

182y - 24y = 2380 - 2064

158y = 316

y = 316/158

y = 2

Substitute y = 2 into (1)

12x + 13y = 170 (1)

12x + 13(2) = 170

12x + 26 = 170

12x = 170 - 26

12x = 144

x = 144/12

x = 12

x = cost of daylily = $12

y = cost of ivy = $2

create a problem using radios of for your guardian/parent or friends solve. write both of your problems and Solutions in your Journal ​

Answers

Answer:

The following,... and uh I don't have a journal ;->

Step-by-step explanation:

You and your 10 friends each have 121 books that you will be bringing to a Best Book Barrage book exchange. Once everyone arrives you count a total of  books. Assuming everyone brings the same amount of books how many people came to the exchange?

Answer: 8,228

Please someone tell me the answer of these questions

Answers

Answer:

VERTICALLY OPP ANGLES

Step-by-step explanation:

please help me guys im desprate at this point ​

Answers

Answer:

Does the answer help you?

How many people can Liam buy lunch for

Answers

Answer:

At most, Liam can only buy lunch for 6 people.

Step-by-step explanation:

It isn't going to be a decimal answer because there can't be half of a person

All you have to do is divide 50 by 8 and round down because you don't want to spend more than 50 dollars.

Writing it mathematically, it would be:

p [tex]\leq[/tex] 6

Find the first five terms. Please solve

Answers

Answer:

a1=3, a2=6, a3=12, a4=24, a5=48

Step-by-step explanation:

a7=a*r^6=192

a10=a*r^9=1536, r^3=8, r=2 and a=3

a1=3, a2=6, a3=12, a4=24, a5=48

Correct gets 5 stars and brainliest

Answers

Answer:

13 mi

Step-by-step explanation:

Since this is a right triangle, we can use the Pythagorean theorem

a^2+b^2 = c^2  where a and b are the legs and c is the hypotenuse

5^2 +12^2 = c^2

25+144 = c^2

169 = c^2

Taking the square root of each side

sqrt(169) = sqrt(c^2)

13 = c

Other Questions
For the equation, determine whether the equation is true for all, some, or no values of x.Explain how you know. In a certain animal species, the probability that a healthy adult female will have no offspring in a given year is 0.24, while the probabilities of 1, 2, 3, or 4 offspring are respectively 0.25, 0.19, 0.17, and 0.15. Find the expected number of offspring. The ( develop) ..... in technology allow astronomers to know more about outer space Is the statement at the top true or false what is the antonym of steep Who was the leader of the socialist party of americia whats the differnce in (5x+4)-(x+2) Question 4 (2 marks)Justin works 14 hours at a normal pay rate of $24.80 per hour and 5 hours of overtime attime and a half. How much should he be paid?I809 wordsLEEnglish (Australia) The mass of an object is 4G and it has a density of 5gm^-3. what is the volume Which of the following statements describes mental disorders? A.Mental disorders are usually only found in individuals with low mental capabilities. B.Mental disorders are best managed without assistance .C.Mental disorders are illnesses that affect a person's emotions, behavior, and thoughts. D.Mental disorders are not true diseases. A Ud le han pedido escrobir un articulo para el periodico de su colegio. Escriba un ensayo de 5 oraciones explicandoles a sus companeros la importancio de comer bien y como evitar problemas de salud All of the following are anticipated effects of a proposed project. Which of these should be considered when computing the cash flow for the final year of the project? Operating cash flow and salvage values only Salvage values and net working capital recovery only Operating cash flow, net working capital recovery, salvage values Net working capital recovery and operating cash flow only Operating cash flow only Identify the true statements regarding hydrogen bonding. Select all that apply. Group of answer choices Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom. A cylindrical tin has a radius of 3 cm. What is the shortes length of a string that can be wound once round the curved surface of the tin?(Takeby =3.14) The sales tax for an item was $18.40 and it cost $460 before tax.Find the sales tax rate. Write your answer as a percentage. Look at image to see question Which of the following is an example of exponential growth?A. Investing $1,000 at an annual interest rate of 3%, compounded monthlyB. A bacterial culture increases by 1,000 bacteria per dayC. The height of a tree increases by 2 feet each yearD. Water drips into a bucket at a rate of 2 pints each minute Which amendment was later repealed? A. Seventeenth Amendment B. Eighteenth Amendment C. Fifteenth Amendment D. Sixteenth Amendment The management of Fuzzy Button Clothing Company controls 58% of the company's stock. The firm did not meet any of its quarterly sales projections for the last year. Some of the firm's institutional investors are worried that the firm's poor performance is partly because management has not been focused on maximizing shareholder wealth. Which of the following measures would the institutional investors most likely want to see implemented? A. They would like to see the size of the board of directors increased, because larger boards usually implement a higher degree of corporate governance. B. They would like to see that the company has an interlocking board of directors with one of the company's strategic partners C. They would like to see that the majority of the company's board of directors is composed of true outsiders. It is reasonable to assume that a firm's management is going to be ultimately motivated to act in their own best interest. It can be a serious problem for shareholders if management's self-interests do not align with shareholders' self-interests. Select the statement that best describes the board of directors' actions in the following scenario: Happy Lion Manufacturing Inc. currently has $1.1 billion in cash on its balance sheet. The CFO thinks the firm will need $600 million in cash to finance operations for the next year. The CFO has recommended that the firm keep the excess cash in a marketable securities portfolio to allow for unexpected costs. However, the board of directors has decided that the firm will pay this money out to the shareholders in the form of a cash dividend. D. The board's decision will give management the incentive to make decisions that are not in the shareholders' best interest. E. The board's decision will help align management's interests with the shareholders' interests. F. The board's decision is extremely risky and not very practical Flash Player WIN 32,0,0.387 Match the vocabulary word to its correct definition.1. mean The mean is the average value of the data you collect. In statistics, you find the mean of your sample. Then you use that mean to approximate the mean of the entire population. If you want the mean of the data to be a good approximation of the mean of the entire population, your need to make sure that you collect a random sample. To find the mean, you find the sum of the data points you collected and divide it by the number of data points in the set. For example, if the data you collected was {3, 3, 6}. Then the mean would be (3 + 3 + 6) 3 = 12 3 = 4. It's important to note that the mean does not have to be a data point in your set. You can generalize the formula as well. If you collect n data points {d1, d2, d3, dn}, then the mean of your data set is . The Greek letter pronounced "mu"is used because the word "mean" begins with the letter "m." It is important that you divide by the number of data points in your set, n. 2. population An experiment is a well-defined procedure under controlled conditions designed to gather data that tests a hypothesis. For example, you want to test the hypothesis that flowers grow faster when they are watered every other day as opposed to every day. Then you could water one set of plants every day and another set of plants every other day. What data would you collect? The height of each plant once a day. What conditions would you need to control? You would need to make sure that the groups of plants are treated the same in every other way by getting the same amount of sun and being maintained at the same temperature, etc. 3. experiment Bias is the preference for a particular group or subset. In the example above, the bias was toward viewers who like sports. When your sample is not chosen at random, you introduce bias into your study. So, in a certain sense, a biased sample is the opposite of a random sample. Why? In a biased sample, some members of the population are more likely to be chosen than others. In a random sample, every member of the population is equally likely to be chosen. Bias may also occur in surveys. See "survey" below for more information on this type of bias. 4. sample A population is the entire group you want to understand. So, in a certain sense, you can think of the population as the "opposite" of the sample because a sample is not the entire population. A sample is chosen subset upon that you use to draw conclusions about the entire population. 5. bias Random means free from bias. So, if you choose a random sample from a population, every member of the population has an equal chance of being chosen. It should be pointed out that this "true randomness" is an ideal which is difficult to achieve in real world experiments conducted on real world populations. That is why statisticians make every effort to ensure their samples chosen as free from bias as is possible, that is, as randomly as possible under real world conditions. 6. survey A sample is a subset chosen from a population. In most cases, you want a random sample. Why? A random sample has the best chance of accurately representing the entire population. 7. random A survey is the means of collecting a sample. In statistics, a survey is often a question or set of questions. It is critical that the questions, like the sample itself, be free from bias. Bias in a question tends to favor one response. As an extreme example of a biased question about colors might be, "Don't you think blue is beautiful and yellow is yucky?" An unbiased form of the question might be, "Which color do you prefer, blue or yellow?" Though careful, statisticians might be concerned about the order in which the colors are offered, so that might further simplify the question to, "What is your favorite color?" This type of question is most free from bias because it does not suggest a response and therefore does not favor a response.