A scientist is trying to determine whether the use of cell phone contributes to brain cancer. For his study, he compares the medical records of subjects who have been diagnosed with brain cancer to the records of healthy subjects. What is the most significant weakness in this type of study?

The test groups must be unusually large to generate significant data.
The relationship between cell phone use and cancer is difficult to determine.
This type of study is expensive, and the data are difficult to analyze.
This type of study must rely on medical records, which are inaccurate.

Answer:

If Julian bought 1 notebook, he would only have enough money for 2 pens

Step-by-step explanation:

Pen = $4.50

Notebook = $3.50

2 pens = $9.

9 + 3.50 = 12.50.

15 - 12.50 = 2.50.

$2.50 is not enough money for another notebook or pen.

Answer:

2 notebooks.

Step-by-step explanation:

To evaluate this you just have to create an equation to solve this problem, it says that Julian has $15 in total, and he has to buy at least one notebook, so you´d have to withdraw the money of a notebook from the total, and the pens cost 4.50 each, we will be expressing the number of pens by "X" and the number of notebooks by "y" so your equation would be like this:

[tex]4.5x+3.5y=15[/tex]

The number of notebooks is one, so you can put it into the equation:

[tex]4.5x+3.5y=15[/tex]

[tex]4.5x+3.5(1)=15[/tex]

Now you clear "x"

[tex]4.5x=15-3.5[/tex]

[tex]4.5x=11.5[/tex]

[tex]x=\frac{11.5}{4.5}[/tex]

[tex]x=2.55[/tex]

Since he can not buy .55 of a pen, he will only be able to buy 2 pens.

Answer:

Step-by-step explanation:

If the line has no x-intercept, then it's a horizontal line with equation

[tex]y=a,\ a\neq0[/tex]

The line passes through the point (0, -4). Therefore the equation of this line is:

[tex]y=-4[/tex]

Answer:

y = 4

Step-by-step explanation:

Since the line has no x-intercept, this means that the line has a slope of 0, meaning it is a horizontal line. So with the equation y = mx + b, mx cancels out to 0 because there is no slope. This leaves y = b, where b = 4. So the answer is y =4

Answer:

x > 8

Step-by-step explanation:

Given

17 < 9 + x ( subtract 9 from both sides )

8 < x , hence

x > 8

Answer:

(4,-47) is the solution

Step-by-step explanation:

4 is x

-47 is y

Just substitute these numbers into the equations and your solution must equal y which is - 47. This solution did equal -47 so its the one

Answer:

X= -4  Y= -15

Step-by-step explanation:

Got Correct On Mypath.

Answer:

the slope of jk is -6/5

the slope of pq is 4/5

the lines are (I don't know what options are given)

Step-by-step explanation:

you can use the x1 y1 formula

[tex]\frac{y2-y1}{x2-x1}[/tex]=[tex]\frac{-7-5}{10-0}[/tex]=[tex]\frac{-12}{10}[/tex]=[tex]\frac{-6}{5}[/tex]

therefore, the slope is -6/5

using the same formula;

tex]\frac{y2-y1}{x2-x1}[/tex]= [tex]\frac{4-(-8)}{0-(-5)}[/tex]=[tex]\frac{12}{15}[/tex]=[tex]\frac{4}{5}[/tex]

therefore, the slope is 4/5

and I would glady re-edit this answer if you can comment what the options for the last one are :)

Answer:

The slope of Jk is -6/5

The slope of PQ is 4/5

The lines are neither parallel or perpendicular

Step-by-step explanation:

Answer:

The other x-intercept is (-2,0)

Step-by-step explanation:

-x^2-5x-6

-(x^2+5x+6)

We know x=-3 is a x-intercept so x+3 is a factor

-(x+3)(        )

The other factor has to be x+2 since 3(2)=6 and 2+3=5

So -x^2-5x-6 is the same as -(x+3)(x+2)

Which means the other x-intercept is (-2,0)

Answer:

a(-1)^(n-1).

Step-by-step explanation:

This is a Geometric Sequence with common ratio r = -1.

The general term is a(-1)^(n-1).

The general term for the sequence a, -a, a, -a, ... is given by the mathematical formula (-1)^(n+1) * a, where n is the term's position in the sequence, starting at n=1 for the first term.

The general term for the sequence a, -a, a, -a, ... can be described using a formula that alternates between a and -a as the sequence progresses. This pattern is a common example of a simple mathematical sequence where the terms alternate in sign.

To express this sequence as a general term, we can use the concept of the n-th term in a sequence. If we let n represent the position of the term in the sequence (starting with n=1 for the first term), we could describe the n-th term using the formula (-1)^(n+1) * a. This formula takes advantage of the fact that raising -1 to an even power results in 1, and raising it to an odd power results in -1, thus alternating the sign of a as n increases.

For example, if n=1, the formula gives (-1)^(1+1) * a = 1 * a = a. If n=2, the formula gives (-1)^(2+1) * a = -1 * a = -a, and so on.

Answer:

-3 degrees C

Step-by-step explanation:

We need to subtract 3 degrees from Thursdays temperature

0 - 3

-3 degrees C

Given the dataset

[tex]x = \{21,\ 31,\ 26,\ 24,\ 28,\ 26\}[/tex]

We start by computing the average:

[tex]\overline{x} = \dfrac{21+31+26+24+28+26}{6}=\dfrac{156}{6}=26[/tex]

We compute the difference bewteen each element and the average:

[tex]x-\overline{x} = \{-6,\ 5,\ 0,\ -2,\ 2,\ 0\}[/tex]

We square those differences:

[tex](x-\overline{x})^2 = \{36,\ 25,\ 0,\ 4,\ 4,\ 0\}[/tex]

And take the average of those squared differences: we sum them

[tex]\displaystyle \sum_{i=1}^n (x-\overline{x})^2=36+25+4+4+0+0=69[/tex]

And we divide by the number of elements:

[tex]\displaystyle \sigma^2=\dfrac{\sum_{i=1}^n (x-\overline{x})^2}{n} = \dfrac{69}{6} = 11.5[/tex]

Finally, we take the square root of this quantity and we have the standard deviation:

[tex]\displaystyle\sigma = \sqrt{\dfrac{\sum_{i=1}^n (x-\overline{x})^2}{n}} = \sqrt{11.5}\approx 3.39[/tex]

To find the standard deviation of the set 21, 31, 26, 24, 28, 26, first calculate the mean, then the squared deviations from the mean, followed by the variance, and finally take the square root of the variance. The standard deviation is approximately 2.52.

The question asks how to find the standard deviation of the numbers 21, 31, 26, 24, 28, 26. To calculate the standard deviation, follow these steps:

Let's calculate it together:

Therefore, the standard deviation of the data set is approximately 2.52.

Answer:

6x^6y^8z^6

Step-by-step explanation:

(3x^3y^4z^4)(2x^3y^4z^2)

= 6x^(3+3) y^(4+4) z^(4+2)

= 6x^6y^8z^6

Answer:

(6x⁶y⁸z⁶)

Step-by-step explanation:

The given expression is (3x³y⁴z⁴) (2x³y⁴z²) and we have to simplify it.

= 6 (x)³⁺³ (y)⁴⁺⁴ (z)⁴⁺²    [Since xᵃ · xᵇ = xᵃ⁺ᵇ]

Therefore, simplified form of the expression is

(6x⁶y⁸z⁶)

Answer:

≈ 36.81 cm ( to 2 dec. places )

Step-by-step explanation:

The perimeter (P) of the sector is calculated as

P = circumference of circle × fraction of circle + radii

  = 2π × 15 × [tex]\frac{26}{360}[/tex] + 30

  = 30π × [tex]\frac{26}{360}[/tex] + 30

  = [tex]\frac{26\pi }{12}[/tex] + 30 ≈ 36.81 cm

Answer:

36.81 cm to the nearest hundredth  (or  30 + 13 π / 6).

Step-by-step explanation:

The perimeter of the circle of which this sector is a part = 2 π 15

= 30 π  cms

So the length of the curved part of the sector = 26 * 30 π  / 360

= 2.167π

The perimeter =  2(15) + 2.167 π

= 36.81 cm.

Answer:

y = 3x + 1

Step-by-step explanation:

The equation is in slope- intercept form

y = mx + c ( m is the slope and c the y- intercept )

Calculate m using the slope formula

m = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (0, 1) and (x₂, y₂ ) = (1, 4) ← 2 ordered pairs from table

m = [tex]\frac{4-1}{1-0}[/tex] = 3

Note the line crosses the y- axis at (0, 1) ⇒ c = 1

y = 3x + 1

Answer:

Step-by-step explanation:

The slope here is -3.

This answer is found by using the formula I clipped below.

Hope that Helps!

Answer:

There are 4,000 milligrams

Step-by-step explanation:

We know that in 1 gram there are 1000 milligrams

To calculate how many milligrams equals 20 grams we perform the following operation

[tex]20\ g*\frac{1000\ mg}{1\ g}=20,000\ mg[/tex]

Then 100 mL of a solution contains 20,000 mg

To calculate how many milligrams there are in 20mL of the solution we perform the following operation

[tex]20\ mL*\frac{20,000\ mg}{100\ mL}=4,000\ mg[/tex]

Answer:

3

Step-by-step explanation:

To find the lower quartile first locate the median.

The median is the middle value of the data set arranged in ascending order.

The data given is in ascending order

0, 1, 3, 3, 4, 4, 4, 5, 6, 6, 8

                    ↑ ← The median is 4

The lower quartile is then the middle value of the data to the left of the median.

0, 1, 3, 3, 4

       ↑ ← the lower quartile is 3

The lower quartile of the data is given as 3

Lower quartile of the data is the median of all the observations till the median of the given observations.

Median is the middle observations of the set of observations.

The median is the mid value which is 4

So, the values till 4 are 0, 1 , 3, 3, 4,

∴  The median is the mid value which are 3

∴ The lower quartile of the data is given as 3

Find more about "Lower quartile" here: https://brainly.com/question/10005803

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Answer:

the values of x, y and z are x= 2, y =-1 and z=1

Step-by-step explanation:

We need to solve the following system of equations.

We will use elimination method to solve these equations and find the values of x, y and z.

2x + 2y + 5z = 7     eq(1)

6x + 8y + 5z = 9     eq(2)

2x + 3y + 5z = 6     eq(3)

Subtracting eq(1) and eq(3)

2x + 2y + 5z = 7

2x + 3y + 5z = 6

-    -       -        -

_____________

0 -y + 0 = 1

-y = 1

=> y = -1

Subtracting eq(2) and eq(3)

6x + 8y + 5z = 9    

2x + 3y + 5z = 6    

-     -      -          -

______________

4x + 5y +0z = 3    

4x + 5y = 3      eq(4)

Putting value of y = -1 in equation 4

4x + 5y = 3

4x + 5(-1) = 3

4x -5 = 3

4x = 3+5

4x = 8

x= 8/4

x = 2

Putting value of x=2 and y=-1 in eq(1)

2x + 2y + 5z = 7

2(2) + 2(-1) + 5z = 7

4 -2 + 5z = 7

2 + 5z = 7

5z = 7 -2

5z = 5

z = 5/5

z = 1

So, the values of x, y and z are x= 2, y =-1 and z=1

Answer:

Step-by-step explanation:

So you can use the special formula for 30-60-90 triangle or you can use the whole Soh Cah Toa thing.

I honestly prefer trig. so a is the opposite side of the 30 deg and 12 is the hyp. This should scream sine to you since sine  goes with opposite/hypotenuse.

sin(30 deg)=a/12

Multiply both sides by 12

giving a=12 sin(30)

Type into calculator unless you know your unit circle well.

a=6

Answer:

a = 6

Step-by-step explanation:

Since the triangle is right use the sine ratio to find a

sin30° = [tex]\frac{opposite}{hypotenuse}[/tex] = [tex]\frac{a}{12}[/tex]

Multiply both sides by 12

12 × sin30° = a, hence

a = 6

Answer:

52

Step-by-step explanation:

1456/ 28 = 52 days

Answer:

52 days

Step-by-step explanation:

If she swims 28 laps a day, it will take her 52 days to reach her goal.

1,456/28 = 52

Answer:

x = 3; y = 6

Step-by-step explanation:

x + 2x = 9

3x = 9

x = 3

Answer:

A.

male long sleeves: 3

Male short sleeves: 0

male rolled up sleeves: 2

Female long sleeves: 0

Female short sleeves: 2

Female rolled up sleeves: 1

B. 0/3

C. 2/5

Step-by-step explanation:

Answer:

Since AB = BE and DB =CE

Step-by-step explanation:

The ratio and of these two give the concept of slope

The last sentence explains why the slope of AB is equal to slope of BC.

It is the measure of steepness of a line.

In the given figure, AD = BE and DB = EC

So, the ratio AD to BE is equal to the ratio BE to EC.

The slope of a line is given by,

slope = rise / run

Which is same as the above mentioned ratio.

Since AD = BE and DB = EC, their proportions are also equal. Therefore the slope of AB is equal to the slope of BC.

To learn more about slope, use the link given below:

https://brainly.com/question/3605446

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Answer:

Micheal is 8, and Tom is 12 years old.

Step-by-step explanation:

To solve this, we can set each of their ages as a variable. Let's say Michael's age is x.

We know Tom is 4 years older than Michael, so Tom's age is x+4.

We also know that their combined age is 20, so if we add both of their ages, we should get 20.

Solving;

[tex]x + (x+4) = 20\\2x+4 = 20\\2x=16\\x=8.[/tex]

So Michael's age is 8, and Tom is 12.

Answer:

Tom is 12 and Michael is 8

Step-by-step explanation:

Answer:

The model represents the expression:

A. 7/8 ÷ 1/8

Step-by-step explanation:

In the question, the number line model represents 7/8 divided into 7 equal units. Each arrow represents a unit and there are a total of seven arrows.

The size of each unit is 1/8 as shown.

Showing that 1/8 divides 7/8 into 7 divisions:

7/8 ÷ 1/8

= 7/8 x 8/1

= 7/1 x 8/8

= 7 x 1

= 7

Hence, the number line represents seven divisions given by 7/8 ÷ 1/8.

Answer:

f(x) = - (x - 3) (x + 4)

Step-by-step explanation:

* Lets explain the graph

- The graph is a parabola, which is the graph of the quadratic function

- The general form of the quadratic function is f(x) = ax² + bx + c

- a is the coefficient of x², if a > 0 the parabola is oped upward, if a < 0

 the parabola is opened down ward

- c is the y-intercept of the parabola means the curve intersect the

  y-axis at point (0 , c)

- The roots (zeroes) of the quadratic function are the x-intercept of the

  parabola means values of x when f(x) = 0

* Now lets solve the problem

- The parabola is downward

∴ The coefficient of x² is negative

- The y-intercept is 12

∴ c = 12

- The x-intercepts are 3 , -4

∴ The zeroes of the function are 3 , -4

∴ x = 3 ⇒ subtract 3 from both sides

∴ x - 3 = 0

∴ x = -4 ⇒ add 4 for both sides

∴ x + 4 = 0

- The factors of f(x) are (x - 3) and (x + 4)

∴ f(x) = -(x - 3)(x + 4)

- Lets find the general form of the function to be sure from the answer

- Multiply the two brackets

∵ f(x) = - [(x)(x) + (x)(4) + (-3)(x) + (-3)(4)] = - [x² + 4x + -3x + -12]

∴ f(x) = - [x² + x - 12] ⇒ multiply the bract by the (-)

∴ f(x) = -x² - x + 12

- Lets check the value of the y-intercept

∵ a = -1 , c = 12

∴ The coefficient of x² is -ve ⇒ the parabola is downward

∴ The y-intercept is 12

∴ f(x) = - (x - 3) (x + 4) is the answer

Answer:

The correct answers are:

(1) The vertical asymptote is x = 0

(2) The horizontal asymptote is y = 0

Step-by-step explanation:

(1) To find the vertical asymptote, put the denominator of the rational function equals to zero.

Rational Function = g(x) = 

Denominator = x = 0

Hence the vertical asymptote is x = 0.

(2) To find the horizontal asymptote, check the power of x in numerator against the power of x in denominator as follows:

Given function = g(x) = 

We can write it as:

g(x) = 

If power of x in numerator is less than the power of x in denominator, then the horizontal asymptote will be y=0.

If power of x in numerator is equal to the power of x in denominator, then the horizontal asymptote will be y=(co-efficient in numerator)/(co-efficient in denominator).

If power of x in numerator is greater than the power of x in denominator, then there will be no horizontal asymptote.

In above case, 0 < 1, therefore, the horizontal asymptote is y =

Hello There!

Economic utility is the amount of satisfaction a consumer receives from the consumption of a particular product or service.

Answer:

The capacity of a good or service to meet the demand of a consumer. The amount of economic utility of a good or service determines what the demand will be for that good or service, which impacts the price that people will be willing to pay to obtain it

Step-by-step explanation:------------------------------------------)-

Answer:

[tex]\frac{300}{t}[/tex] chairs at each table

Step-by-step explanation:

Total number of chairs : 300

Total number of tables : t

If we divide 300 chairs equally among t tables, then each table must have 300 chairs ÷ t tables = [tex]\frac{300}{t}[/tex] chairs at each table.

Answer:

b

Step-by-step explanation:

25 minutes

Answer:

B.25

Step-by-step explanation:

To find the amount of minutes, divide the total amount of feet from the feet per minute:

60000/2400 = 25

B. 25 is the amount needed to climb to 60,000 feet.

~

bearing in mind that the squared variable is the "x", and thus this is a vertical parabola, therefore its axis of symmetry will come from the x-coordinate of its vertex.

[tex]\bf \textit{vertex of a vertical parabola, using coefficients} \\\\ f(x)=\stackrel{\stackrel{a}{\downarrow }}{-2}x^2\stackrel{\stackrel{b}{\downarrow }}{+8}x\stackrel{\stackrel{c}{\downarrow }}{-7} \qquad \qquad \left(-\cfrac{ b}{2 a}~~~~ ,~~~~ c-\cfrac{ b^2}{4 a}\right) \\\\\\ \left(-\cfrac{8}{2(-2)}~,~-7-\cfrac{8^2}{4(-2)} \right)\implies \left( \cfrac{8}{4}~,~-7+8 \right)\implies (2,1) \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \stackrel{\textit{axis of symmetry}}{x=2}~\hfill[/tex]

7/8 is tricky to do on a computer, but I will say that it is 87.5 percent or 0.875.

Do you know how to do normal long division? This is like that. Just after the decimal point, drop a 0 down.

I hope this helps!

Answer:

7/8 = .875     7/8=87.5%

Step-by-step explanation:

Divide 1/4(.25) by 2 and you get 1/8(.125)

Multiply .125 by 7 which gives you .875.

For the percent just multiply .875 by 100

Hope this helps.