Answer:
The mean of the sampling distribution is always equal to the mean of the population.
The mean of the sampling distribution of the sample mean is 45.
Given that,
The mean of the random variable X is 45.We need to find out the mean of the sampling distribution.Based on the above information, the calculation is as follows:
= mean of the random variable X
= 45
As the sampling distribution mean should always be equivalent to the population mean.
Therefore we can conclude that the mean of the sampling distribution of the sample mean is 45.
Learn more: brainly.com/question/521501
The width of a rectangular slab of concrete is 7 m less than the length. The area is 98 m squared. Find the dimensions
Answer:
Length = 14 m, Width = 7 m
Step-by-step explanation:
Let the length is l and width is b.
Width, b = l-7
Area of the rectangle, A = 98 m²
We know that, the area of a rectangle is as follow :
[tex]A=lb[/tex]
So,
[tex]98=l(l-7)\\\\98=l^2-7l\\\\l^2-7l-98=0\\\\l^2+7l-14l-98=0\\\\l(l+7)-14(l+7)=0\\\\l=14,-7[/tex]
Length can't be negative. So,
Width, b = 14-7 = 7 m
So, the dimensions of the rectangle are 14 m and 7 m respectively.
write 16.76 correct to the nearest whole number
Answer:
17
Step-by-step explanation:
because they are both above 5 so add 1
4x-1,9x-1,7x-3 find the perimeter
20x-5
Answer:
Solution given;
perimeter=sum of all sides
=4x-1+9x-1+7x-3=20x-5
The perimeter of the line segments 4x - 1, 9x - 1, and 7x - 3 is 20x - 5.
To find the perimeter of the given line segments, you need to add up the lengths of all the line segments.
The lengths of the line segments are:
4x - 1,
9x - 1,
7x - 3.
To find the perimeter, add these lengths together:
Perimeter = (4x - 1) + (9x - 1) + (7x - 3)
= 4x + 9x + 7x - 1 - 1 - 3
= 20x - 5.
Therefore, the perimeter of the line segments 4x - 1, 9x - 1, and 7x - 3 is 20x - 5.
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Overige
1) IF A = {2,3, 5, 7, 11 OR Write four subdivisions of this set.
2) A set of sub-sets of any set from the figure below.
с
5
25
35
D
15
10
30
20
3) Find out which of the following sets is a subset of which set of figures.
1
с
B
A
1) X = A set of self-contained lines
U
Y- set of all the elements above line AB
Answer:
the answae is D THEN C THE. 1
Find domain of (x^2+3)+[tex]\sqrt{x} 3x-1[/tex]
Answer:
= x^2 + 3 + √3x^2 - 1
Step-by-step explanation:
Remove parentheses: (a) = a
= x^2 + 3 + √x . 3x - 1
x . 3x = 3x^2
= x^2 + 3 + √3x^2 - 1
Simplify
b. 3a + 4b-2a-b
4 나
V
216 x
Х
18
Answer:
a+3b
Step-by-step explanation:
3a+4b-2a-b
=3a-2a+4b-b
=a+3b
An experiment consists of tossing a coin and rolling a six-sided die simultaneously. Step 1 of 2 : What is the probability of getting a head on the coin and the number 2 on the die
Answer:
[tex]\frac{1}{12}[/tex] probability of getting a head on the coin and the number 2 on the die
Step-by-step explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
Independent events:
If two events, A and B are independent, the probability of both events happening is the multiplication of the probabilities of each event happening, that is:
[tex]P(A \cap B) = P(A)P(B)[/tex]
Probability of getting a head on the coin:
Head or tails, fair coin, so:
[tex]P(A) = \frac{1}{2}[/tex]
Probability of getting the number 2 on the die:
6 numbers, one of which is 2, so:
[tex]P(B) = \frac{1}{6}[/tex]
What is the probability of getting a head on the coin and the number 2 on the die?
[tex]P(A \cap B) = P(A)P(B) = \frac{1}{2} \times \frac{1}{6} = \frac{1}{12}[/tex]
[tex]\frac{1}{12}[/tex] probability of getting a head on the coin and the number 2 on the die
What are the solutions to the system of equations graphed below
what is the best deal for diet coke?
12oz. for $.99
64oz. for $.2.99
128oz. for $4.99
Answer:
128 for 4.99
64 for 2.99 times 2 is more than 4.99.
12 oz. for 0.99 is also more than 4.99.
HELP! AAHHHHH SOMEBODY HELP!
If each square of the grid below is $0.5\text{ cm}$ by $0.5\text{ cm}$, how many square centimeters are in the area of the blue figure?
Answer:
8.50 cm²
Step-by-step explanation:
The dimension of each square is given as 0.5cm by 0.5cm
The area of the a square is, a²
Where, a = side length
Area of each square = 0.5² = 0.25cm
The number of blue colored squares = 34
The total area of the blue colored squares is :
34 * 0.25 = 8.50cm²
f(x) = (x + 1)^2
Determine for each x-value whether it is in the domain of f
or not.
Answer:
All of them are in the domain.
Step-by-step explanation:
The function is f(x)= (x+1)^2. If you simplify this, you get y=x^2+2x+1=0. This is a quadratic that opens upwards. There are no gaps in the x values and no impossible values. The domain is all real numbers and all the answer choices are real numbers.
What is the value of q?
2/5
2/14
Answer:
2√14 prob I'm not 100% sure
what are the zeroes of f(x)=(x-7)(x+8)
Answer:
The zeroes of f(x) = (x-7)(x+8) are 7 and -8.
Step-by-step explanation:
You have to figure out what makes each of the equal to zero.
Step 1 : Make the 2 equations both equal 0.
x-7 = 0
x+8 = 0
Step 2: Solve for x
x-7 = 0
x=7
x+8 = 0
x=-8
So 7 and -8 are both zeroes of this function.
Solve a triangle with a =5, b =6, and c = 7. Round to the nearest tenth.
Answer:
<A ≈ 45 degrees
<B ≈ 57 degrees
<C ≈ 78 degrees
Step-by-step explanation:
Hi there!
1) Find <C with the law of cosines
Typically, we want to solve for the angle opposite the largest side first.
Law of cosines: [tex]cosC=\frac{a^2+b^2-c^2}{2(a)(b)}[/tex]
Plug in given values
[tex]cosC=\frac{5^2+6^2-7^2}{2(5)(6)}\\cosC=\frac{1}{5}\\C=cos^-^1(\frac{1}{5} )\\C=78[/tex]
Therefore, <C is approximately 78 degrees.
2) Find <B with the law of cosines
[tex]cosB=\frac{a^2+c^2-b^2}{2(a)(c)}[/tex]
Plug in given values
[tex]cosB=\frac{5^2+7^2-6^2}{2(5)(7)}\\cosB=\frac{19}{35}\\B=cos^-^1(\frac{19}{35})\\B=57[/tex]
Therefore, <B is approximately 57 degrees.
3) Find <A
The sum of the interior angles of a triangle is 180 degrees. To solve for <A, subtract <B and <C from 180:
180-57-78
= 45
Therefore, <A is 45 degrees.
I hope this helps!
the old building at the back of the school is badly in need of repair. the company Hsa and the executive are planning to renovate the building to accommodate a new music room. There are 15 rooms in the building and the dimension of the rooms to be redone with tiles are 6m long and 4 m wide. ted the tile man has 500 one meter square tiles.
Explain how you would estimate whether Ted has enough tiles to cover all the kitchen floors in the entire apartment building?
How many tiles, each measuring 1 square meter, are needed to cover one room floor?
How many tiles are needed to cover all the floors in the entire building? Show your work?
Answer:
a. If the area of the tiles is greater than or equal to the area of all the rooms.
b. 24
c. 360
Step-by-step explanation:
a. Explain how you would estimate whether Ted has enough tiles to cover all the kitchen floors in the entire apartment building?
Ted would have enough tiles if the area of the tiles is greater than or equal to the area of all the rooms. Since we have 500 one meter square tiles, we have 500 m² of tiles.
Since the rooms are 6 m long and 4 m wide, the area of each room is 6 m × 4 m = 24 m². Since there are 15 rooms, the area of all the rooms is 15 × 24 m² = 360 m².
Since the area of the tiles = 500 m² is greater than the area of the rooms = 360 m², Ted would have enough tiles to cover all kitchen floors in the entire apartment building.
b. How many tiles, each measuring 1 square meter, are needed to cover one room floor?
Since the area of each room floor is 24 m² and the area of each tile is 1 m², so the number of 1 square meter tiles needed to cover each floor is n = area of floor/area of tile = 24 m²/1 m² = 24.
c. How many tiles are needed to cover all the floors in the entire building?
Since 24 tiles are needed to cover each floor and there are 15 rooms in the building, we would require 24 tiles/room × 15 rooms/building = 360 tiles.
So we require 360 tiles.
hey Plz help me fast it's important.
Answer:
Step-by-step explanation:
a) 52 is divisible by 4 and 5 - 2 = 3
b) 63 is divisible by 9 and 3*2 = 6 -> ten digit
c) 50 is divisible by 10 and 5 + 0 = 5
d) 72 is divisible by 6 and 7*2 = 14
Javier volunteers in community events each month. He does not do more than five events in a month. He attends exactly five events 25% of the time, four events 30% of the time, three events 20% of the time, two events 15% of the time, one event 5% of the time, and no events 5% of the time. Find the probability that Javier volunteers for less than three events each month. P (x < 3) = 2 Find the expected number of events Javier volunteers in a month. 3.6 It is given that x must be below a certain value, which limits the rows to use in the PDF table. What is the sum of the probabilities of those rows?
Answer:
[tex]P(x < 3) = 25\%[/tex]
[tex]E(x) = 3[/tex]
Step-by-step explanation:
The given parameters can be represented as:
[tex]\begin{array}{ccccccc}x & {5} & {4} & {3} & {2} & {1}& {0} & P(x) & {25\%} & {30\%} & {20\%} & {15\%} & {5\%} & {5\%} \ \end{array}[/tex]
Solving (a): P(x < 3)
This is calculated as:
[tex]P(x < 3) = P(x = 0) + P(x = 1) + P(x =2)[/tex] ----- i.e. all probabilities less than 3
So, we have:
[tex]P(x < 3) = 5\% + 5\% + 15\%[/tex]
[tex]P(x < 3) = 25\%[/tex]
Solving (b): Expected number of events
This is calculated as:
[tex]E(x) = \sum x * P(x)[/tex]
So, we have:
[tex]E(x) = 5 * 25\% + 4 * 30\% + 3 * 20\% + 2 * 15\% + 1 * 5\% + 0 * 5\%[/tex]
[tex]E(x) = 125\% + 120\% + 60\% + 30\% + 5\% + 0\%[/tex]
[tex]E(x) = 340\%[/tex]
Express as decimal
[tex]E(x) = 3.40[/tex]
Approximate to the nearest integer
[tex]E(x) = 3[/tex]
The center of the circle is located (3'8), and the circle has a radius that is 5 units long. What is the general form of the equation for the circle
9514 1404 393
Answer:
x² +y² -6x -16y +48 = 0
Step-by-step explanation:
Given:
circle center: (3, 8)circle radius: 5Find:
general form equation for the circle
Solution;
The standard form equation for the circle is ...
(x -h)² +(y -k)² = r² . . . . . circle with radius r centered at (h, k)
(x -3)² +(y -8)² = 5²
Subtracting 25 and expanding this will give the general form.
x² -6x +9 +y² -16y +64 -25 = 0
x² +y² -6x -16y +48 = 0
_____
Additional comment
"General form" of an equation is usually the form f(x,y) = 0, where f(x, y) is written in "standard form," with terms in lexicographical order and decreasing degree.
Which of the following is an even function?
g(x) = (x – 1)2 + 1
g(x) = 2x2 + 1
g(x) = 4x + 2
g(x) = 2x
Answer:
B. g(x) = 2x² + 1Step-by-step explanation:
Even function has following property:
g(x) = g(-x)It is easy to show this works with the second choice only. All the others don't work:
g(x) = (x - 1)² + 1g(-x) = (-x - 1)² + 1This is not correct as x - 1 ≠ -x - 1 so as their squares, so g(x) ≠ g(-x)
The last two choices are not even similarly.
Answer:
B. g(x) = 2x2 + 1
Correct on edge
math help plz
how to solve parabola and its vertex, how to understand easily and step by step with an example provided please
Answer:
The general equation for a parabola is:
y = f(x) = a*x^2 + b*x + c
And the vertex of the parabola will be a point (h, k)
Now, let's find the values of h and k in terms of a, b, and c.
First, we have that the vertex will be either at a critical point of the function.
Remember that the critical points are the zeros of the first derivate of the function.
So the critical points are when:
f'(x) = 2*a*x + b = 0
let's solve that for x:
2*a*x = -b
x = -b/(2*a)
this will be the x-value of the vertex, then we have:
h = -b/(2*a)
Now to find the y-value of the vertex, we just evaluate the function in this:
k = f(h) = a*(-b/(2*a))^2 + b*(-b/(2*a)) + c
k = -b/(4*a) - b^2/(2a) + c
So we just found the two components of the vertex in terms of the coefficients of the quadratic function.
Now an example, for:
f(x) = 2*x^2 + 3*x + 4
The values of the vertex are:
h = -b/(2*a) = -3/(2*2) = -3/4
k = -b/(4*a) - b^2/(2a) + c
= -3/(4*2) - (3)^2/(2*2) + 4 = -3/8 - 9/4 + 4 = (-3 - 18 + 32)/8 = 11/8
A
(8x - 5) in.
B
The perimeter of parallelogram ABCD is 46 inches.
What is DA?
03 in
O 4 in
8 in.
O 19 in
D
С
(3x + 10) in
[Not drawn to scale]
Help please!!!!!!!!!!!!!!!!!!
A game-show spinner has these odds of stopping on particular dollar values: 55% for $5, 20% for $25, 15% for $50, and 10% for $500. What are the odds of a player winning $5 or $25
Answer: 75%
Step-by-step explanation:
Which expression is equivalent to -9x-1y-9/-15x5y-3?
Answer: -9x-1y-9/
Step-by-step explanation:
Answer: b
Step-by-step explanation:
I really dont like edge
Urgent help!!!
*Picture included
Answer:
3x+4
Step-by-step explanation:
When you factor 9x^2+24x+16, it factors to (3x+4)^2
Factoring 9x^2 - 16 factors to (3x+4)(3x-4)
Therefore the common factor is 3x+4
I hope this helps!
Could someone help me
Hello,
I have only found 113 solutions (i have num 15 given)
nb= 1 ::: 27*n + 98= 30*n + 56===> n= 1 4
nb= 2 ::: 28*n + 95= 30*n + 67===> n= 1 4
nb= 3 ::: 29*n + 65= 30*n + 17===> n= 4 8
nb= 4 ::: 29*n + 65= 30*n + 18===> n= 4 7
nb= 5 ::: 29*n + 65= 30*n + 47===> n= 1 8
nb= 6 ::: 29*n + 65= 30*n + 48===> n= 1 7
nb= 7 ::: 29*n + 74= 30*n + 16===> n= 5 8
nb= 8 ::: 29*n + 74= 30*n + 18===> n= 5 6
nb= 9 ::: 29*n + 74= 30*n + 56===> n= 1 8
nb= 10 ::: 29*n + 74= 30*n + 58===> n= 1 6
nb= 11 ::: 30*n + 16= 29*n + 74===> n= 5 8
nb= 12 ::: 30*n + 17= 29*n + 65===> n= 4 8
nb= 13 ::: 30*n + 18= 29*n + 65===> n= 4 7
nb= 14 ::: 30*n + 18= 29*n + 74===> n= 5 6
nb= 15 ::: 30*n + 47= 29*n + 65===> n= 1 8
nb= 16 ::: 30*n + 48= 29*n + 65===> n= 1 7
nb= 17 ::: 30*n + 56= 27*n + 98===> n= 1 4
nb= 18 ::: 30*n + 56= 29*n + 74===> n= 1 8
nb= 19 ::: 30*n + 58= 29*n + 74===> n= 1 6
nb= 20 ::: 30*n + 67= 28*n + 95===> n= 1 4
nb= 21 ::: 36*n + 97= 40*n + 25===> n= 1 8
nb= 22 ::: 38*n + 59= 40*n + 27===> n= 1 6
nb= 23 ::: 38*n + 65= 40*n + 27===> n= 1 9
nb= 24 ::: 38*n + 69= 40*n + 15===> n= 2 7
nb= 25 ::: 39*n + 78= 45*n + 6===> n= 1 2
nb= 26 ::: 39*n + 82= 40*n + 15===> n= 6 7
nb= 27 ::: 39*n + 82= 40*n + 17===> n= 6 5
nb= 28 ::: 39*n + 82= 40*n + 65===> n= 1 7
nb= 29 ::: 39*n + 82= 40*n + 67===> n= 1 5
nb= 30 ::: 40*n + 15= 38*n + 69===> n= 2 7
nb= 31 ::: 40*n + 15= 39*n + 82===> n= 6 7
nb= 32 ::: 40*n + 17= 39*n + 82===> n= 6 5
nb= 33 ::: 40*n + 25= 36*n + 97===> n= 1 8
nb= 34 ::: 40*n + 27= 38*n + 59===> n= 1 6
nb= 35 ::: 40*n + 27= 38*n + 65===> n= 1 9
nb= 36 ::: 40*n + 65= 39*n + 82===> n= 1 7
nb= 37 ::: 40*n + 67= 39*n + 82===> n= 1 5
nb= 38 ::: 46*n + 87= 50*n + 39===> n= 1 2
nb= 39 ::: 46*n + 87= 52*n + 9===> n= 1 3
nb= 40 ::: 47*n + 68= 50*n + 29===> n= 1 3
nb= 41 ::: 47*n + 83= 50*n + 26===> n= 1 9
nb= 42 ::: 47*n + 98= 51*n + 6===> n= 2 3
nb= 43 ::: 47*n + 98= 53*n + 2===> n= 1 6
nb= 44 ::: 48*n + 63= 50*n + 29===> n= 1 7
nb= 45 ::: 48*n + 73= 52*n + 9===> n= 1 6
nb= 46 ::: 49*n + 63= 51*n + 7===> n= 2 8
nb= 47 ::: 49*n + 72= 53*n + 8===> n= 1 6
nb= 48 ::: 49*n + 78= 52*n + 30===> n= 1 6
nb= 49 ::: 49*n + 87= 56*n + 3===> n= 1 2
nb= 50 ::: 50*n + 26= 47*n + 83===> n= 1 9
nb= 51 ::: 50*n + 29= 47*n + 68===> n= 1 3
nb= 52 ::: 50*n + 29= 48*n + 63===> n= 1 7
nb= 53 ::: 50*n + 39= 46*n + 87===> n= 1 2
nb= 54 ::: 52*n + 30= 49*n + 78===> n= 1 6
nb= 55 ::: 57*n + 92= 63*n + 8===> n= 1 4
nb= 56 ::: 58*n + 72= 60*n + 34===> n= 1 9
nb= 57 ::: 58*n + 73= 60*n + 49===> n= 1 2
nb= 58 ::: 58*n + 79= 60*n + 31===> n= 2 4
nb= 59 ::: 58*n + 97= 60*n + 13===> n= 4 2
nb= 60 ::: 59*n + 47= 62*n + 8===> n= 1 3
nb= 61 ::: 59*n + 71= 60*n + 23===> n= 4 8
nb= 62 ::: 59*n + 71= 60*n + 28===> n= 4 3
nb= 63 ::: 59*n + 71= 60*n + 43===> n= 2 8
nb= 64 ::: 59*n + 71= 60*n + 48===> n= 2 3
nb= 65 ::: 59*n + 74= 63*n + 2===> n= 1 8
nb= 66 ::: 59*n + 78= 61*n + 30===> n= 2 4
nb= 67 ::: 59*n + 84= 61*n + 30===> n= 2 7
nb= 68 ::: 59*n + 87= 61*n + 3===> n= 4 2
nb= 69 ::: 60*n + 13= 58*n + 97===> n= 4 2
nb= 70 ::: 60*n + 23= 59*n + 71===> n= 4 8
nb= 71 ::: 60*n + 28= 59*n + 71===> n= 4 3
nb= 72 ::: 60*n + 31= 58*n + 79===> n= 2 4
nb= 73 ::: 60*n + 34= 58*n + 72===> n= 1 9
nb= 74 ::: 60*n + 43= 59*n + 71===> n= 2 8
nb= 75 ::: 60*n + 48= 59*n + 71===> n= 2 3
nb= 76 ::: 60*n + 49= 58*n + 73===> n= 1 2
nb= 77 ::: 61*n + 30= 59*n + 78===> n= 2 4
nb= 78 ::: 61*n + 30= 59*n + 84===> n= 2 7
nb= 79 ::: 65*n + 89= 70*n + 24===> n= 1 3
nb= 80 ::: 68*n + 59= 72*n + 3===> n= 1 4
nb= 81 ::: 68*n + 91= 70*n + 45===> n= 2 3
nb= 82 ::: 69*n + 43= 70*n + 15===> n= 2 8
nb= 83 ::: 69*n + 43= 70*n + 18===> n= 2 5
nb= 84 ::: 69*n + 43= 70*n + 25===> n= 1 8
nb= 85 ::: 69*n + 43= 70*n + 28===> n= 1 5
nb= 86 ::: 69*n + 48= 72*n + 3===> n= 1 5
nb= 87 ::: 69*n + 52= 70*n + 14===> n= 3 8
nb= 88 ::: 69*n + 52= 70*n + 18===> n= 3 4
nb= 89 ::: 69*n + 52= 70*n + 34===> n= 1 8
nb= 90 ::: 69*n + 52= 70*n + 38===> n= 1 4
nb= 91 ::: 69*n + 54= 71*n + 8===> n= 2 3
nb= 92 ::: 69*n + 58= 73*n + 2===> n= 1 4
nb= 93 ::: 69*n + 82= 75*n + 4===> n= 1 3
nb= 94 ::: 69*n + 85= 74*n + 20===> n= 1 3
nb= 95 ::: 70*n + 14= 69*n + 52===> n= 3 8
nb= 96 ::: 70*n + 15= 69*n + 43===> n= 2 8
nb= 97 ::: 70*n + 18= 69*n + 43===> n= 2 5
nb= 98 ::: 70*n + 18= 69*n + 52===> n= 3 4
nb= 99 ::: 70*n + 24= 65*n + 89===> n= 1 3
nb= 100 ::: 70*n + 25= 69*n + 43===> n= 1 8
nb= 101 ::: 70*n + 28= 69*n + 43===> n= 1 5
nb= 102 ::: 70*n + 34= 69*n + 52===> n= 1 8
nb= 103 ::: 70*n + 38= 69*n + 52===> n= 1 4
nb= 104 ::: 70*n + 45= 68*n + 91===> n= 2 3
nb= 105 ::: 74*n + 20= 69*n + 85===> n= 1 3
nb= 106 ::: 76*n + 93= 80*n + 45===> n= 1 2
nb= 107 ::: 79*n + 45= 82*n + 6===> n= 1 3
nb= 108 ::: 79*n + 54= 83*n + 6===> n= 1 2
nb= 109 ::: 80*n + 45= 76*n + 93===> n= 1 2
nb= 110 ::: 87*n + 64= 90*n + 25===> n= 1 3
nb= 111 ::: 87*n + 65= 90*n + 23===> n= 1 4
nb= 112 ::: 90*n + 23= 87*n + 65===> n= 1 4
nb= 113 ::: 90*n + 25= 87*n + 64===> n= 1 3
HELPPP
3p-4-8p<-19
i need the steps as well
9514 1404 393
Answer:
p > 3
Step-by-step explanation:
3p -4 -8p < -19 . . . . . . given
-5p -4 < - 19 . . . . . . . . collect terms
-5p < -15 . . . . . . . . . . . add 4
p > 3 . . . . . . . . . . . . . . divide by -5 (reverses the inequality symbol)
A student has test scores of 75 and 82respectively. What is the student’s average score for a third test
Answer:
78.5 (I think 90% sure)
Step-by-step explanation:
sum of both scores
75+82 = 157
average for a third test
157÷2=78.5
Question A cotton farmer produced 390 pounds per acre after 4 years of operating. After 9 years, he was producing 460 pounds per acre. Assuming that the production amount has been increasing linearly, estimate the production per acre 7 years after he started farming. Your answer should just be a numerical value. Do not include units in your answer. Provide your answer below:
A hotel manager believes that 23% of the hotel rooms are booked. If the manager is right, what is the probability that the proportion of rooms booked in a sample of 610 rooms would differ from the population proportion by less than 3%
Answer:
0.9216 = 92.16% probability that the proportion of rooms booked in a sample of 610 rooms would differ from the population proportion by less than 3%
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
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]
A hotel manager believes that 23% of the hotel rooms are booked.
This means that [tex]p = 0.23[/tex]
Sample of 610 rooms
This means that [tex]n = 610[/tex]
Mean and standard deviation:
[tex]\mu = p = 0.23[/tex]
[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.23*0.77}{610}} = 0.017[/tex]
What is the probability that the proportion of rooms booked in a sample of 610 rooms would differ from the population proportion by less than 3%?
p-value of Z when X = 0.23 + 0.03 = 0.26 subtracted by the p-value of Z when X = 0.23 - 0.03 = 0.2. So
X = 0.26
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.26 - 0.23}{0.017}[/tex]
[tex]Z = 1.76[/tex]
[tex]Z = 1.76[/tex] has a p-value of 0.9608
X = 0.2
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.2 - 0.23}{0.017}[/tex]
[tex]Z = -1.76[/tex]
[tex]Z = -1.76[/tex] has a p-value of 0.0392
0.9608 - 0.0392 = 0.9216
0.9216 = 92.16% probability that the proportion of rooms booked in a sample of 610 rooms would differ from the population proportion by less than 3%
