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?
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
How many exterior walls does the building have?
Answer:
18
Step-by-step explanation:
360÷20=18
twentycharactersignorethis
the building has 16 exterior walls
Given the system of equations, what is the solution? 2x+y = -1 х- у = -5
Answer:
x=-2, y=3
Step-by-step explanation:
make it easy first, solve for x in the second equation: x= -5+y.
then sub that in for the other x: 2(-5+y)+y= -1
now combine like terms: -10+3y= -1
solve for y: 3y=9, y= 3
then replace y for your second equation: x-3= -5
solve for x= -5+3.... so then its -2
check by replacing all variables with your new solutions:
2(-2), which is -4+3 does equal -1
(-2) -3 does equal -5.
your answers are x=-2, y=3
Please help me understand
Answer:
A is is correct since the interquatile or a is 15 since 15 plus 15 equals 30 and 20 plus 20 equals 40
B is incorrect since the interquare are not both 30
C is incorrect since both interquatiles are wrong
D is incorrect since the standrard devations are off
The time to complete an exam is approximately Normal with a mean of 48 minutes and a standard deviation of 3 minutes. The bell curve below represents the distribution for testing times. The scale on the horizontal axis is equal to the standard deviation. Fill in the indicated boxes.
Answer:
This means the average amount of time is 48 minutes but many people will do it in 45 to 51
Hope This Helps!!!
PLEASEEEE HELP QUICKKKK
Given:
Line A goes through (0,y) and (-2,0).
Line B goes through (1,2) and (3,10).
To find:
The value of y for which the system of given linear equation (equation of line A and line B) has no solutions.
Solution:
Two linear equation has no solutions if they are parallel line.
Slope formula:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
We know that the slopes of two parallel lines are the same.
So, the given system of given linear equation has no solutions if
Slope of line A = Slope of line B
[tex]\dfrac{0-y}{-2-0}=\dfrac{10-2}{3-1}[/tex]
[tex]\dfrac{-y}{-2}=\dfrac{8}{2}[/tex]
[tex]\dfrac{y}{2}=4[/tex]
Multiply both sides by 2.
[tex]\dfrac{y}{2}\times 2=4\times 2[/tex]
[tex]y=8[/tex]
Therefore, the required value of y is 8.
-6c< -12
what will the answear be
Answer:c>2
Step-by-step explanation:
-6c (divide) (-6) > -12 (divide) (-6)
c>-12 (divide) (-6)
c>12 (divide) 6
c> 2
four times a certain number decreased by twice the same number gives 17. the number is
Answer:
8.5
Step-by-step explanation:
how do I solve this equation?
[tex]x + 8y = 20 \\ 2x + 4y = 4[/tex]
Answer:
Subtract x x from both sides of the equation. 8y=20−x 8 y = 20 - x. Divide each term by 8 8 and simplify.
Solve for x 2x-4y=4. 2x−4y=4 2 x - 4 y = 4. Add 4y 4 y to both sides of the equation. 2x=4+4y 2 x = 4 + 4 y. Divide each term by 2 2 and simplify.
1. The curved surface area of a cylinder of height 21cm is
660cm", find its radius. please help me .....
I will give brainliest.
Answer:
21 times 660 and then you will get the answer
Someone please help with the questions on this picture!! URGENT!!!
Answer:
A) Independent
B) Dependent
Step-by-step explanation:
A) If we take a marble out and put the marble back, it means we have restored the sample to what it was initially and thus it doesn't affect probability of making another selection.
Thus, this is an independent event.
B) A card is taken from a deck of cards without replacement and set aside. Then after that another card is taken from the first sample, this means that the first sample size has now reduced and thus the first card taken affects the probability of the second card to be picked. Thus, this is a dependent event.
How many numbers lie between the squares of 39 and 40
Answer:
i guess its 1...
Step-by-step explanation:
Answer:
79 numbers
Step-by-step explanation:
39 x 39 = 1521 ( Find the square of 39)
40 x 40 = 1600 (Find the square of 40)
1600 - 1521 = 79 ( Finding the difference of the two squares)
Please anybody? Line intergal
Parameterize the path by
r (x) = (x, x + 2)
with 0 ≤ x ≤ 2. Then
r' (x) = (1, 1) ==> ||r' (x)|| = √(1² + 1²) = √2
and the line integral is
[tex]\displaystyle\int_Lxy\,\mathrm ds=\sqrt2\int_0^2x(x+2)\,\mathrm dx=\boxed{\frac{20\sqrt2}3}[/tex]
Three-fourths (one-fourth x + 8) minus (one-half x + 2) = StartFraction 3 Over 8 EndFraction (4 minus x) minus one-fourth?
Answer:
if I am understood your question correctly, X would be 84/29
Step-by-step explanation:
Complete the table of inputs and outputs for the given function. g(x) = 3 - 8x g() 0 -5 3 Reset
Answer:
Step-by-step explanation:
19. Which of the following would best be solved using factoring the difference of squares?
O x^3 + 5x^2 - 9x - 45 = 0
O 3x² + 12x = 8
O x^2 - 25 = 0
O x^2 + 3x – 10 = 0
Please hurry!
Answer:
x² + 3x - 10 = 0
x² - 25 = 0
Write the formulae of area and volume of different solid shapes. Find out the variables and constants in them.
Answer:
Step-by-step explanation:
1 . Sphere :
[tex]Surface \ Area = 4\pi r^2\\\\ Volume = \frac{4}{3} \pi r^3[/tex]
Variable is ' r '
Others Constants.
2. Cone :
[tex]Surface \ Area = \p r^2 + \pi rs[/tex] [tex][ \ s = \sqrt { r^2 + h^2 } \ , r = base \ radius, h = height \ ][/tex]
[tex]Volume = \frac{1}{3} \pi r^2 h[/tex]
Variables are ' r ' and ' h '
Others constants.
3. Cuboid ( Rectangular Prism )
[tex]Surface \ Area = 2 ((l\times b) + ( b \times h) + ( l \times h)) \\\\Volume = l \times \ b \times \ h[/tex]
Variables : l , b , h
Constant is 2
4. Cylinder
[tex]Surface \ Area = 2 \pi r h + 2 \pi r^2 \\\\Volume = \pi r^2 h[/tex]
Variables : ' r ' and ' h '
Others constants..
Answer:
shapes. cuboid. cube. cylinder. prism. sphere. pyramid. rightcircularcone. volumeformula. l×w×h. v=a . 3. v=πr . 2. h. v=b×h. v=( 3. 4)πr . 3. v=( 3. 1)×h×b. v=( 3. 1)πr . 2. h. variables. l=length,w=width,h=height. a=side. r=radius,h=height. b=base,h=height. r=radiusofthesphere. b=areaofthebase,h=heightofthepyramid. r=radiusofthecircularbase,h=height
Step-by-step explanation:
Find the midpoint of the line segment.
Answer:
-2,-3
Step-by-step explanation:
Suppose we are sending a digital signal which is a string of 0s and 1s of length five. (Example stringsare 00101, 11000, 10101 are all 5 bit strings.) When we send the message, each bit (0 or 1) is sentindependently and there is some chance that the bit is corrupted. Namely, each time we send a 0 thereis a 5% chance that a 1 is received and each time we send a 1 there is a 5% chance a 0 is received.Suppose we send a message of length 5, what is the probability that an incorrect message is received
Answer:
0.7738 = 77.38% probability that an incorrect message is received.
Step-by-step explanation:
For each bit, there are only two possible outcomes. Either it is corrupted, or it is not. The probability of a bit being corrupted is independent of any other bit. This means that the binomial probability distribution is used to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
5% probability a bit is sent incorrectly:
This means that [tex]p = 0.05[/tex]
Message of length 5
This means that [tex]n = 5[/tex]
What is the probability that an incorrect message is received?
This is the probability of at least one incorrect bit, which is:
[tex]P(X \geq 1) = 1 - P(X = 0)[/tex]
In which
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{5,0}.(0.05)^{0}.(0.95)^{5} = 0.7738[/tex]
0.7738 = 77.38% probability that an incorrect message is received.
Defined the total variation distance to be a distance TV(P,Q) between two probability measures P and Q. However, we will also refer to the total variation distance between two random variables or between two pdfs or two pmfs, as in the following.
Compute TV(X,X+a) for any a∈(0,1), where X∼Ber(0.5).
TV(X,X+a) = ?
Answer:
1
Step-by-step explanation:
Computing Tv(X, X + a ) for any a∈(0,1)
Given that : X∼Ber(0.5)
∴ The probability mass function
P(X = 1 ) = 0.5
P(X = 0) = ( 1 - 0.5 )
and expectation E[X] = 0.5
hence ; TV ( X, X + a ) = 1
A knight wanted to visit a princess.
He had to arrive at exactly 17h00.
If he travelled at 15 km per hour, he would arrive one hour too early.
If he travelled at 10 km per hour, he would arrive one hour too late.
Questions : 1- At what time did he leave?
2- What distance did he travel?
3- At what speed did he travel?
Answer:
He had to arrive at 5:00pm
If he traveled at 15km per hour, he would arrive one hour too early
If he traveled at 10km per hour, he would arrive one hour too late.
At what time did he leave, what distance did he travel, and at what speed did he travel
:
Let d = distance traveled
:
Write an time equation; time = dist/speed
Travel time at 10 km/hr - travel time at 15 km/h = 2 hrs
d%2F10 - d%2F15 = 2
Multiply by 30
3d - 2d = 30(2)
d = 60 km is the distance
:
Find the travel time at 15 km/hr
60%2F15 = 4 hrs
:
let s = speed required to get there on time
:
required travel time - 15km/hr travel time = 1
60%2Fs - 4 = 1 hr
60 - 4s = 1s
60 = 1s + 4s
60 = 5s
s = 12 km/hr to arrive on time
:
Required travel time: 60%2F12 = 5 hrs
He would have to leave at noon
;
Summarize, depart at noon, travel for 5 hrs at 12 km/hr, a dist of 60 km
Step-by-step explanation:
How do I solve this and do the explanation of it
Answer:
180-66
114
hope it helps mark as brainlist
PLEASE ANSWER ASAP FOR BRANLIEST!!!!!!!!!!!!
Answer:
1. zero
2. seven over eight
3. one over three
4. one
5. one over two
PLEASE GIVE BRAINLYIST!!
What is the answer to this question
Answer:
its b because when subtract 30-24=6
Consider functions f, g, and h.
F(x) = 3x^3 + 9x^2 al- 12x g(x) = x - 1 h(x) = 3x2 + 12x
Which expression defines function h?
The relation between the functions f(x), g(x), and h(x) will be f(x)/g(x) is equal to h(x). Then the correct option is B.
What is a function?A statement, principle, or policy that creates the link between two variables is known as a function. Functions are found all across mathematics and are required for the creation of complex relationships.
The functions are given below.
f(x) = 3x³ + 9x² - 12x
g(x) = x - 1
h(x) = 3x² + 12x
The function f(x) can be written as
f(x) = 3x(x² + 3x - 4)
f(x) = 3x(x² + 4x - x - 4)
f(x) = 3x(x + 4)(x - 1)
f(x) = (x - 1)(3x² + 12)
Then divide the function f(x) by the function g(x), then we have
f(x) / g(x) = (x - 1)(3x² + 12) / (x - 1)
f(x) / g(x) = (3x² + 12)
f(x) / g(x) = h(x)
More about the function link is given below.
https://brainly.com/question/5245372
#SPJ2
Answer:
B
Step-by-step explanation:
edmentum
an isosceles triangle has one angel that measure 30 degree what is the measure of the other two angles that are equal?
2. A bag contains one red, one blue and one white marble. One marble is chosen at random
from the bag, and then replaced into the bag. A second marble is chosen.
a) Draw a probability tree and find the sample space.
(3 marks)
Answer:
Step-by-step explanation:
Can someone help me with this question please.
Answer:
The rule is to divide the weight of the bag by 4 to find the number of marbles.
Step-by-step explanation:
The rule is to divide the weight of the bag by 4 to find the number of marbles.
If you horizontally stretch the linear parent function, f(x) = x, by a factor of 3,
what is the equation of the new function?
A. g(x) = x - 3
B. g(x) = 3x
O C. g(x) = 3 - x
D. g(x) = 3 *
SUBMIT
Answer:
The equation of the new function is [tex]g(x) = \frac{x}{3}[/tex]
Step-by-step explanation:
Horizontally stretching a function:
Horizontally stretching a function f(x), by a factor of a, means that:
[tex]g(x) = f(\frac{x}{a})[/tex]
In this question:
[tex]f(x) = x[/tex], horizontally stretched by a factor of 3, so [tex]a = 3[/tex], and:
[tex]g(x) = f(\frac{x}{3}) = \frac{x}{3}[/tex]
The equation of the new function is [tex]g(x) = \frac{x}{3}[/tex]
write all the integers between the pairs in increasing orders A.-30 and -23 B. -3 and 3
please help
Answer:
Step-by-step explanation:
-30, -29,-28,-27,-26,-25,-24,-23
B) -3,-2,-1,0,1,2,3
