A study of the effect of television commercials on 12-year-old children measured their attention span, in seconds. The commercials were for clothes, food, and toys.

Clothes Food Toys
43 30 52
24 38 58
42 46 43
35 54 49
28 47 63
31 42 53
17 34 48
31 43 58

Required:
a. Find the values of mean and standard deviation.
b. Is there a difference in the mean attention span Of the children for the various commercials?

Answers

Answer 1

Answer:

(a)

Mean

[tex]\bar x_1 = 31.375[/tex]

[tex]\bar x_2 = 41.75[/tex]

[tex]\bar x_3 = 53.00[/tex]

Standard deviation

[tex]\sigma_1 = 8.73[/tex]

[tex]\sigma_2 = 7.65[/tex]

[tex]\sigma_3 = 6.04[/tex]

(b) Yes, there is a difference in the mean

Step-by-step explanation:

Solving (a): The mean and standard deviation of each commercial

This is calculated as:

[tex]\bar x = \frac{\sum x}{n}[/tex]

For clothes:

[tex]\bar x_1 = \frac{43+24+42+35+28+31+17+31}{8}[/tex]

[tex]\bar x_1 = \frac{251}{8}[/tex]

[tex]\bar x_1 = 31.375[/tex]

For food:

[tex]\bar x_2 = \frac{30+38+46+54+47+42+34+43}{8}[/tex]

[tex]\bar x_2 = \frac{334}{8}[/tex]

[tex]\bar x_2 = 41.75[/tex]

For toys:

[tex]\bar x_3 = \frac{52+58+43+49+63+53+48+58}{8}[/tex]

[tex]\bar x_3 = \frac{424}{8}[/tex]

[tex]\bar x_3 = 53.00[/tex]

The sample standard deviation is:

[tex]\sigma = \sqrt{\frac{\sum(x - \bar x)^2}{n-1}}[/tex]

For clothes:

[tex]\sigma_1 = \sqrt{\frac{(43 - 31.375)^2 +.............+(31 - 31.375)^2}{8-1}}[/tex]

[tex]\sigma_1 = \sqrt{\frac{533.875}{7}[/tex]

[tex]\sigma_1 = \sqrt{76.2678571429}[/tex]

[tex]\sigma_1 = 8.73[/tex]

For food:

[tex]\sigma_2 = \sqrt{\frac{(30 - 41.75)^2 +............+(43 - 41.75)^2}{8-1}}[/tex]

[tex]\sigma_2 = \sqrt{\frac{409.5}{7}}[/tex]

[tex]\sigma_2 = \sqrt{58.5}[/tex]

[tex]\sigma_2 = 7.65[/tex]

For toys:

[tex]\sigma_3 = \sqrt{\frac{(52-53.00)^2+...................+(58-53.00)^2}{8}}[/tex]

[tex]\sigma_3 = \sqrt{\frac{292}{8}}[/tex]

[tex]\sigma_3 = \sqrt{36.5}[/tex]

[tex]\sigma_3 = 6.04[/tex]

Solving (b): Difference in mean in the commercials;

In (a), we have:

[tex]\bar x_1 = 31.375[/tex]

[tex]\bar x_2 = 41.75[/tex]

[tex]\bar x_3 = 53.00[/tex]

[tex]\bar x_1 \ne \bar x_2 \ne \bar x_3[/tex]

Hence, there is a difference in their means


Related Questions

ASAP there are three marbles in a bag. One is red and two are black. What is the probability of picking a black marble first, putting it back in the bag and then picking a black marble? Use the following probability to find the answer.

Answers

Answer:

[tex] \frac{4}{9} [/tex]

Step-by-step explanation:

[tex]p = \frac{favorable \: outcomes}{total \: outcomes} = \frac{4}{9} [/tex]

Answer:  Choice D)  4/9

=============================================================

Explanation:

The probability you get a black marble on the first selection is 2/3 since we have 2 black marbles out of 2+1 = 3 total.

We put the marble back and then we have 2/3 as the probability of selecting another black marble on the second try. Nothing has changed because we put the marble back. That means the events are independent.

So we get (2/3)*(2/3) = 4/9 as the probability of selecting 2 black marbles in a row (with replacement).

Rectangle ABCD translates 4 units down and 2 units to the right to form rectangle A'B'C'D'. The vertices of rectangle ABCD are labeled in alphabetical order going clockwise around the figure. If AB = 3 units and AD = 5 units, what is the length of B'C'?

Answers

Answer:

The length of BC is 14 units.

Step-by-step explanation:

[tex]hope \: \: it \: \: helps} \beta \alpha \infty [/tex]

The length of B'C' is 0 units.

What is translation?

It is the movement of the shape in left, right, up, and down direction.

The translated shape will have the same shape and shape.

There is a positive value when translated to the right and up.

There is a negative value when translated to the left and down.

We have,

The length of AD = 5 units.

Since the rectangle translates down by 4 units,

The length of A'D' =5 units.

The width of the original rectangle is AB, which is 3 units.

Since the rectangle translates to the right by 2 units,

The width of the new rectangle = 3 units.

Now,

The length of B'C' is the same as the length of AD', which is 5 units.

Subtracting 5 units from 5 units gives us a length of 0 units.

Thus,

The length of B'C' is 0 units.

Learn more about translation here:

https://brainly.com/question/12463306

#SPJ7

If using the method of completing the square to solve the quadratic equation x^2+15x+21=0, which number would have to be added to "complete the square"?

Answers

Step-by-step explanation:

the answer is in the above image

Answer:

my answer is 225/5 sorry comments for wrong

3 3/4 × 2 2/9 please
Help ‍♀️‍♀️‍♀️

Answers

[tex]\implies {\blue {\boxed {\boxed {\purple {\sf { \: 8 \frac{1}{3}\:(or) \:8.333}}}}}}[/tex]

[tex]\sf \bf {\boxed {\mathbb {Step-by-step\:explanation:}}}[/tex]

[tex]3 \frac{3}{4} \times 2 \frac{2}{9} [/tex]

➺[tex] \: \frac{15}{4} \times \frac{20}{9} [/tex]

➺[tex] \: \frac{300}{36} [/tex]

➺[tex] \: \frac{25}{3} [/tex]

➺[tex] \: 8 \frac{1}{3} [/tex]

➺[tex] \: 8.333[/tex]

[tex]\large\mathfrak{{\pmb{\underline{\pink{Mystique35 }}{\orange{❦}}}}}[/tex]

1/6 of ______ equals 9

What is the blank?

Answers

Answer:

54

Step-by-step explanation:

1/6 × y = 9

y ÷ 6 = 9

y ÷ 6 × 6 = 9 × 6

y = 54

Sketch the region enclosed by the given curves and calculate its area.
y=4-x^2 ,y=0

The answer is 32/3. But how do I get to that answer?

Answers

Answer:

Step-by-step explanation:

1.) we need to find the bounds of integration which is just the points of intersection

here is it (-2,0) and (2,0)

which means we will integrate from -2 to 2

next, we take the upper equation and subtract that from the lower one

kind of confusing but it would look like (sketch it out if you're not sure)

(4-x²)-0= 4-x²

then we can integrate

[tex]\int\limits^2_{-2} {4-x^2} \, dx =4x-\frac{x^3}{3}|_{-2}^{2}=(4*(2)-\frac{2^3}{3})-(4(-2)-\frac{-2^3}{3})=5.333333-(-5.3333333)= 10.666666667=\frac{32}{3}[/tex]

Need help finding the factor of 2y^2-2y-4

Answers

Answer:

hope it helps you............

Answer:

2(y - 2)(y + 1)

Step-by-step explanation:

Given

2y² - 2y - 4 ← factor out 2 from each term

= 2(y² - y - 2) ← factor the quadratic

Consider the factors of the constant term (- 2) which sum to give the coefficient of the y- term (- 1)

The factors are - 2 and + 1, since

- 2 × 1 = - 2 and - 2 + 1 = - 1 , then

y² - y - 2 = (y - 2)(y + 1)

Then

2y² - 2y - 4 = 2(y - 2)(y + 1) ← in factored form

Solve for y.
r/3-2/y=s/5

Answers

Answer:

y = 2 / (r/3 - s/5)

Step-by-step explanation:

r/3 - 2/y = s/5

add 2/y to both sides

r/3 = s/5 + 2/y

Subtract s/5 from both sides

r/3 - s/5 = 2/y

multiply both sides by y

y(r/3 - s/5) = 2

Divide both sides by r/3 - s/5

y = 2 / (r/3 - s/5)

A trinomial is a perfect square when two terms are
a. Positive
b.negative
c. Neither positve
d. Either negative

Answers

Answer:

a trinomial is a perfect square trinomial if it can be factorized into a binomial multiplies to itself. In a perfect square trinomial, two of your terms will be perfect squares.

Answer fast please and thanks!

Answers

Answer:

tan 30 = x / 15

General Formulas and Concepts:

Trigonometry

[Right Triangles Only] SOHCAHTOA[Right Triangles Only] tanθ = opposite over adjacent

Step-by-step explanation:

Step 1: Define

Identify variables

Angle θ = 30°

Opposite Leg = x

Adjacent Leg = 15

Step 2: Solve for x

Substitute in variables [tangent]:                                                                     tan 30 = x / 15

Answer:

3rd one

Step-by-step explanation:

Recall that

Sin = opposite over hypotenuse

Cos = adjacent over hypotenuse

Tan = opposite over adjacent

For the angle with a measure of 30 degrees we are given it's adjacent side length and need to find it's opposite side length

When dealing with opposite and adjacent we use tangent

If tan = opposite over adjacent

Then tan30 = x / 15 and the correct answer choice is the third one

If f(x) = - 2x +5 and g(x)=x2-1, then f(-3)+g(2) =​

Answers

Answer:

[tex]{ \tt{f(x) = - 2x + 5}} \\ { \boxed{ \bf{f( - 3) = - 2( - 3) + 5 = 11}}} \\ \\ { \tt{g(x) = {x}^{2} - 1}} \\ { \boxed{ \bf{g(2) = {2}^{2} - 1 = 3}}} \\ f( - 3) + g(2) = 11 + 3 \\ = 14[/tex]

Alec bakes spherical rolls of bread. Each roll is about 8cm
wide. What is the approximate volume of each roll? Use
3.14 to approximate a.

Answers

Answer:

Step-by-step explanation:

2143.57

Find the distance between the pair of points: (0,1) and (1,0)

Answers

Answer:

sqrt(1^2 + 2^2)

[tex]\sqrt{2}[/tex]

Step-by-step explanation:

please help me please help me please help me please help me please help me please help me please​

Answers

Answer:

Q3. 9

Q4. 6

Step-by-step explanation:

which equation is the inverse of 5y+4=(×+3)^2+1/2?​

Answers

Answer:

The inverse is -3 ±sqrt(5x+7/2)

Step-by-step explanation:

5y+4=(x+3)^2+1/2?

To find the inverse, exchange x and y

5x+4=(y+3)^2+1/2​

Solve for y

Subtract 1/2

5x+4 -1/2=(y+3)^2+1/2​-1/2

5x+8/2 -1/2=(y+3)^2+1/2​-1/2

5x+7/2 = (y+3)^2​

Take the square root of each side

±sqrt(5x+7/2) =sqrt( (y+3)^2​)

±sqrt(5x+7/2) = (y+3)

Subtract 3 from each side​

-3 ±sqrt(5x+7/2) = y+3-3

-3 ±sqrt(5x+7/2) = y

The inverse is -3 ±sqrt(5x+7/2)

the sum of two consecutive numbers is 2x+3. What are the numbers

Answers

Answer: 2 and 3

Step-by-step explanation:

its numbers

Hi, could someone help me solve this. so the question says to find the area of the shaded part (in black) , in terms of pie (π). the length of the square is 12 cm. the radius of the circle is 6cm. i came with the answer of (144-36π)/4. is this ok? below is the picture of the question. ​

Answers

Answer:

yes but can be simplified

Step-by-step explanation:

area of shaded part = ( area of square - area of circle ) / 4

= [tex]\frac{12^2-\pi (6)^2}{4}[/tex]

= [tex]\frac{144-36\pi }{4}[/tex]

= [tex]\frac{144}{4}[/tex] - [tex]\frac{36\pi }{4}[/tex]

= 36 - 9π

Chung has 6 trucks and 5 cars in his toy box. Brian has 4 trucks and 5 cars in his toy box.

Which is the correct comparison of their ratios of trucks to cars?
StartFraction 6 Over 4 EndFraction less-than StartFraction 5 Over 5 EndFraction
StartFraction 6 Over 4 EndFraction greater-than StartFraction 5 Over 5 EndFraction
StartFraction 6 Over 5 EndFraction less-than StartFraction 4 Over 5 EndFraction
StartFraction 6 Over 5 EndFraction greater-than StartFraction 4 Over 5 EndFraction

Answers

Given:

Chung has 6 trucks and 5 cars in his toy box.

Brian has 4 trucks and 5 cars in his toy box.

To find:

The correct comparison of their ratios of trucks to cars.

Solution:

The ratio of trucks to cars is defined as:

[tex]\text{Ratio}=\dfrac{\text{Number of trucks}}{\text{Number of cars}}[/tex]

Chung has 6 trucks and 5 cars in his toy box. So, the ratio of trucks to cars is:

[tex]\text{Ratio}=\dfrac{6}{5}[/tex]

Brian has 4 trucks and 5 cars in his toy box.

[tex]\text{Ratio}=\dfrac{4}{5}[/tex]

We know that,

[tex]6>4[/tex]

[tex]\dfrac{6}{5}>\dfrac{4}{5}[/tex]

Therefore, the correct option is D.

Answer:

what the guy above me said

Step-by-step explanation:

so yeah he is right points

differentiate loge(x/x^2+7)​

Answers

Answer:

1+1=11 2+2=22 ok na yan kuya or ate

(View attachment)

a) Write ordered pairs.
b) Write the domain and range.
c) Why isn't the relation a function?
d) Which ordered pair should be removed to make the relation a function?

Answers

Answer:

in a relationship that maps elements from one set (the inputs) into elements from another set (the outputs), the usual notation for the ordered pairs is:

(x, y), where x is the input and y is the output.

In this case, the point where the arrow starts is the input, and where the arrow ends is the output.

a)

The ordered pairs are:

(28, 93)

(17, 126)

(52, 187)

(34, 108)

(34, 187)

b) The domain is the set of the inputs, in this case the domain is the set where all the arrows start, then the domain is:

{17, 28, 34, 52}

And the range is the set of the outputs, in this case the range is:

{93, 108, 126, 187}

c) A function is a relationship where the elements from the domain, the inputs, can be mapped into only one element from the range.

In this case, we can see that the input {34} is being mapped into two different outputs, then this is not a function.

d) We can remove one of the two ordered pairs where the input is {34},

So for example, we could remove:

(34, 108)

And then the relation would be a function.

Gỉaỉ pt
2x^2×(2x^2+3)=2-x^2 ai giải giúp vs

Answers

2x²×(2x²+3)=2-x²

[tex]x = \frac{1}{2} , - \frac{1}{2} ,i \sqrt{2} , - i \sqrt{2} [/tex]

At the beginning of a population study, a city had 320,000 people. Each year since, the population has grown by 2.1%. Lett be the number of years since start of the study. Let y be the city's population. Write an exponential function showing the relationship between y and t. ​

Answers

Answer:

y = 320,000(2.1)^t

Step-by-step explanation:

uhm, im not very good at explaining, but everytime the year increases, the population will exponentially increase, that's why 't' is an exponent

Answer:

[tex]y=320000(1.021)^t[/tex]

Step-by-step explanation:

To increase something by x% mulitply it by (1+x)

in other words, to increase sometihng by 2.1% mulitply it by

(1+.021) or 1.021

because we are mulitplying 320000 by 1.021 each year we can write the equation as

y=320000(1.021)^t

Consider the graph below: Point T(-2; 3) is a point on the Cartesian Plane such that B is the angle of inclination of OT. T(-2;3) у х 2.1 Calculate the following without the use of a calculator: a) tanſ b) 13 sin B.cosB (2)​

Answers

Answer:

(a) - 3/2

(b) - 78/25

Step-by-step explanation:

According to the trigonometry, the tangent of any angle is the ratio of rise to the run of the right angle triangle .

The sine of an angle is the ratio of rise to the hypotenuse of the right angle triangle.

The cosine of an angle is the ratio of run to the hypotenuse of the right angle triangle.

(a)

[tex]tan\beta = \frac{3}{-2} = \frac{-3}{2}[/tex]

(b)

[tex]13 sin\beta cos \beta = 13\times \frac{3}{\sqrt{3^2+2^2}}\times\frac{-2}{\sqrt{3^2+2^2}}\\\\13 sin\beta cos\beta = \frac{- 78}{25}[/tex]

Solve the equation 2x^2 + 3 – 41 = –15 to the nearest tenth.

Hellllpppp

Answers

9514 1404 393

Answer:

 x = {-4.4, +2.9}

Step-by-step explanation:

We assume you want to solve ...

  2x^2 +3x -41 = -15

Adding 41 and factoring out the leading coefficient gives ...

  2(x^2 +3/2x) = 26

Dividing by 2 makes it ...

  x^2 +3/2x = 13

We can add the square of half the x-coefficient to "complete the square."

  x^2 +3/2x +(3/4)^2 = 13 +(3/4)^2

  (x +3/4)^2 = 13.5625 . . . . write the left side as a square

  x +3/4 = ±√13.5625 . . . . . take the square root

  x = -0.75 ±3.683 = {-4.433, +2.933} . . . . subtract 3/4 and evaluate

The solutions are approximately x = -4.4 and x = 2.9.

Simplify the expression

Answers

Answer:

6

Step-by-step explanation:

3 sqrt(20) / sqrt(5)

We know that sqrt(a) /sqrt(b) = sqrt(a/b)

3 sqrt(20/5)

3 sqrt(4)

3 *2

6

what the person above me said

A right rectangular container is 10 cm wide and 24 cm long and contains water to a depth of 7cm. A stone is placed in the water and the water rises 2.7 cm. Find the volume of the stone.

Answers

Answer:

The volume of the rock is 648 cm^3

Step-by-step explanation:

Likely the only dimension that is free to move is the depth of 7 cm.

Volume of the Rock = L * W * h1

L = 24

W = 10

h1 = 2.7

V = 24 * 10 * 2.7

V = 648 cm^3

The ice cream man just ended his shift for the day. Let 1/2x^2 6/11x + 8 represent the amount of chocolate ice cream bars he sold. Let 5/9x^2 + 2/3 represent the amount of vanilla ice cream bars he sold. Finally let 1/3x^2 + 4x + 4/3 represent the amount of strawberry ice cream bars he sold. Select all the statements that are true

a. The total amount of ice cream bars sold can be represented by the expression 25/18x^2+ 50/11x +10
b. The total amount of ice cream bars sold can be represented by the expression 25/18x^2 + 172/33x +28/3
c. He sold 1/6x^2 + 50/11x + 28/3 more chocolate than strawberry ice cream bars.
d. He sold 1/6x^2 - 38/11x + 20/3 more chocolate than strawberry ice cream bars.

Answers

Answer:

A and D

Step-by-step explanation:

Total ice cream bars sold = sum of chocolate sold , vanilla and strawberry ice-creams sold.

=(1/2)x2 + (6/11)x + 8 + (5/9)x2 + (2/3) +(1/3)x2 + 4x +(4/3) (Given in the question)

=(25/18)x2 + (50/11)x + 10 (Adding terms corresponding to x2,x ,constant respectively)

Difference in chocolate and strawberry bars =[ (1/2)x2 + (6/11)x + 8] - [(1/3)x2 + 4x +(4/3)]

= (1/6)x2 - (38/11)x +(20/3)

So, the correct options are A and D

9x5
pls help meeeeeeeeee

Answers

Answer:

45

hope this helps

Answer:

45

Step-by-step explanation:

9x5=45

Rewrite the equation by completing the square.
x^2 + 7x + 12 = 0

Answers

Answer:

x^2 + 7x + 12 = 0

x^2 + 7x  = -12

(+3)(+4)=0

=−3

=−4

I also love r        o      blox

Hope This Helps!!!

Answer:

(x + [tex]\frac{7}{2}[/tex] )² - [tex]\frac{1}{4}[/tex] = 0

Step-by-step explanation:

Given

x² + 7x + 12 = 0

To complete the square

add/subtract ( half the coefficient of the x- term)² to x² + 7x

x² + 2([tex]\frac{7}{2}[/tex] )x + [tex]\frac{49}{4}[/tex] - [tex]\frac{49}{4}[/tex] + 12 = 0

(x + [tex]\frac{7}{2}[/tex] )² - [tex]\frac{49}{4}[/tex] + [tex]\frac{48}{4}[/tex] = 0 , that is

(x + [tex]\frac{7}{2}[/tex] )² - [tex]\frac{1}{4}[/tex] = 0

Find an equation for the line parallel to 3x-5y=2 with​ y-intercept (0,1/5). Write the answer in ​ slope-intercept form.

Answers

y= 3x/5 - 2/5 .i think
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