Answer:
The z-score for 1880 is 1.34.
The z-score for 1190 is -0.88.
The z-score for 2130 is 2.15.
The z-score for 1350 is -0.37.
And the z-score of 2130 is considered to be unusual.
Step-by-step explanation:
The complete question is: A standardized exam's scores are normally distributed. In recent years, the mean test score was 1464 and the standard deviation was 310. The test scores of four students selected at random are 1880, 1190, 2130, and 1350. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 1880 is nothing. (Round to two decimal places as needed.) The z-score for 1190 is nothing. (Round to two decimal places as needed.) The z-score for 2130 is nothing. (Round to two decimal places as needed.) The z-score for 1350 is nothing. (Round to two decimal places as needed.) Which values, if any, are unusual? Select the correct choice below and, if necessary, fill in the answer box within your choice. A. The unusual value(s) is/are nothing. (Use a comma to separate answers as needed.) B. None of the values are unusual.
We are given that the mean test score was 1464 and the standard deviation was 310.
Let X = standardized exam's scores
The z-score probability distribution for the normal distribution is given by;
Z = [tex]\frac{X-\mu}{\sigma}[/tex] ~ N(0,1)
where, [tex]\mu[/tex] = mean test score = 1464
[tex]\sigma[/tex] = standard deviation = 310
S, X ~ Normal([tex]\mu=1464, \sigma^{2} = 310^{2}[/tex])
Now, the test scores of four students selected at random are 1880, 1190, 2130, and 1350.
So, the z-score of 1880 = [tex]\frac{X-\mu}{\sigma}[/tex]
= [tex]\frac{1880-1464}{310}[/tex] = 1.34
The z-score of 1190 = [tex]\frac{X-\mu}{\sigma}[/tex]
= [tex]\frac{1190-1464}{310}[/tex] = -0.88
The z-score of 2130 = [tex]\frac{X-\mu}{\sigma}[/tex]
= [tex]\frac{2130-1464}{310}[/tex] = 2.15
The z-score of 1350 = [tex]\frac{X-\mu}{\sigma}[/tex]
= [tex]\frac{1350-1464}{310}[/tex] = -0.37
Now, the values whose z-score is less than -1.96 or higher than 1.96 are considered to be unusual.
According to our z-scores, only the z-score of 2130 is considered to be unusual as all other z-scores lie within the range of -1.96 and 1.96.
the box plots shows the price for two different brands of shoes
Answer:
A. The interquartile range (IQR) for brand A, $10, is less than the IQR for brand B, $25.
Step-by-step explanation:
The most appropriate measure that can be used to compare the SPREAD of the data of the 2 brands plotted on a box plot, is the Interquartile range (IQR).
Interquartile range is the difference between Q3 and Q1.
Q3 is the value which lies at the end of the rectangular box, while the Q1 lies at the beginning of the box.
From the box plot given,
IQR for brand A = 80 - 70 = $10
IQR for brand B = 50 - 25 = $25
Therefore, the correct option is "A. The interquartile range (IQR) for brand A, $10, is less than the IQR for brand B, $25."
On the maturity date of a $10,800, 6-month, 8% note, the borrower sends a check that includes the principal and all of the interest due on the note. What is the amount of the borrower's check?
Answer: $ 11,232.00
Step-by-step explanation:
Given: Amount = $ 10,800
Interest Rate = 8% =0.08
Time in Months= 6.00
Formula :
Interest on Note = (Amount)× (Interest Rate) × ((Time in Months) /12)
= (10800)× (0.08)× (6/12)
= $432
The amount of the borrower's check =(Amount + Interest on Note)
= $ (10,800+432)
= $ 11,232.00
Hence, The amount of the borrower's check = $ 11,232.00
The Bookstall Inc. is a specialty bookstore concentrating on used books sold via the Internet. Paperbacks are $1.35 each, and hardcover books are $3.50. Of the 60 books sold last Tuesday morning, 55 were paperback and the rest were hardcover. What was the weighted mean price of a book? (Round your answer to 2 decimal places.)
Answer:
dddddd okaksy ogvurn
Step-by-step explanation:
d
(-1, 4) and (-2, 2).
Answer:
Slope : 2
slope-intercept: y = 2x + 6
Point-slope (as asked): y - 4 = 2 (times) (x + 1)
standered: 2x - y = -6
Step-by-step explanation:
Sketch the region enclosed by the given curves. Decide whether to integrate with respect to x or y. Draw a typical approximating rectangle. y = x2 − 4x y = 3x
Answer:
Hello your question is incomplete attached is the missing part the second curve ; y = 3x is incomplete so i would solve the problem taking the second curve as ; y = 3x + 8 ( giving you the general methodology )
answer : y = ( 5,32) , x = ( -1,8 )
area of shaded region = 90.673
Step-by-step explanation:
The given curves ; [tex]y = x^2 - 4x\\y = 3x +8[/tex]
solving the above curves simultaneously
[tex]x^2-4x = 3x + 8[/tex]
x^2 - 7x - 8 = 0
( x + 1 )(x - 8 ) = 0
hence X = ( -1 , 8 )
Therefore y = 3x + 8
when x = -1 , y = -3 + 8 = 5
when x = 8 , y = 24 + 8 = 32
hence y = ( 5, 32 )
attached below is the sketched region
Integrating the curves to determine the shaded area in respect to x = ( -1, 8)
∫ [( 3x +8 ) - ( x^2 - 4x ) ] dx
∫ ( -x^2 +7x + 8 ) dx
= { - x^3/3 + 3x^2 + 8x }
= { - 8^3/3 + 3(64) + 64} - { -1^3/3 + 3 - 8 }
= {-170.66 + 192 + 64 } - { -1/3 - 5 }
= -170.66 + 192 + 64 + 5.333 = 90.673 ( area of the shaded region )
The volume of a rectangular prism is the products it’s dimensions. If the dimensions of a rectangle prism are approximately 1.08 feet,5.25 feet, and 3.3 feet ,what is the approximate volume of the cube?Express your answer using an approximate level of accuracy.
Answer:
18.711
Step-by-step explanation:
Volume = L * W * H
V = 1.08 * 5.25 * 3.3
1.08 * 5.25 = 5.67
5.67 * 3.3 =
V = 18.711
What is the sign of -1.69+(-1.69)
Answer: Negative sign
Adding two negative values results in another negative value.
-1.69 + (-1.69) = -3.38
It's like starting $1.69 in debt and then adding 1.69 dollars of more debt. You'll slide further into debt being $3.38 in debt total.
The sign is negative as the value of -1.69 + (-1.69) is -3.38.
What is an expression?An expression is a way of writing a statement with more than two variables or numbers with operations such as addition, subtraction, multiplication, and division.
Example: 2 + 3x + 4y = 7 is an expression.
We have,
-1.69 + (-1.69)
= -1.69 - 1.69
= -3.38
This means,
The sign is negative.
Thus,
The value of -1.69 + (-1.69) is -3.38.
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Find the first five terms of the sequence of partial sums. (Round your answers to four decimal places.) [infinity] (−5)n + 1 n!
Answer:
25.0000 + -37.5000 + 66.6667 + -63.5416 + 66.6667
Step-by-step explanation:
The actual formatting of the question has been attached to this response.
From the question,
Let the sequence of terms be [tex]b_{n}[/tex] i.e
[tex]b_{n}[/tex] = [tex]\frac{(-5)^{n+1} }{n!}[/tex]
Let the sequence of partial sums be [tex]S_{n}[/tex] i.e
[tex]S_{n}[/tex] = s₁ + s₂ + s₃ + . . . + sₙ
Therefore the first five terms of the sequence of partial sums will be S₅ i.e
S₅ = s₁ + s₂ + s₃ + s₄ + s₅
Where;
s₁ = b₁
s₂ = b₁ + b₂ = s₁ + b₂
s₃ = b₁ + b₂ + b₃ = s₂ + b₃
s₄ = b₁ + b₂ + b₃ + b₄ = s₃ + b₄
s₅ = b₁ + b₂ + b₃ + b₄ + b₅ = s₄ + b₅
Where;
b₁ can be found by substituting n = 1 into equation (i) as follows;
[tex]b_{1}[/tex] = [tex]\frac{(-5)^{1+1} }{1!}[/tex]
[tex]b_{1}[/tex] = 25
[tex]b_{1}[/tex] = 25.0000
Recall that
s₁ = b₁
∴ s₁ = 25.0000 to 4 decimal places
--------------------------------------------------------------------------
b₂ can be found by substituting n = 2 into equation (i) as follows;
[tex]b_{2}[/tex] = [tex]\frac{(-5)^{2+1} }{2!}[/tex]
[tex]b_{2}[/tex] = -62.5
[tex]b_{2}[/tex] = -62.5000
Recall that
s₂ = s₁ + b₂
∴ s₂ = 25.000 + -62.5000 = -37.5000
-----------------------------------------------------------------------------------------
b₃ can be found by substituting n = 3 into equation (i) as follows;
[tex]b_{3}[/tex] = [tex]\frac{(-5)^{3+1} }{3!}[/tex]
[tex]b_{3}[/tex] = 104.1667
Recall that
s₃ = s₂ + b₃
∴ s₃ = -37.5000 + 104.1667 = 66.6667
--------------------------------------------------------------------------------
b₄ can be found by substituting n = 4 into equation (i) as follows;
[tex]b_{4}[/tex] = [tex]\frac{(-5)^{4+1} }{4!}[/tex]
[tex]b_{4}[/tex] = -130.2083
Recall that
s₄ = s₃ + b₄
∴ s₄ = 66.6667 + -130.2083 = -63.5416
-------------------------------------------------------------------------
b₅ can be found by substituting n = 5 into equation (i) as follows;
[tex]b_{5}[/tex] = [tex]\frac{(-5)^{5+1} }{5!}[/tex]
[tex]b_{5}[/tex] = 130.2083
Recall that
s₅ = s₄ + b₅
∴ s₅ = -63.5416 + 130.2083 = 66.6667
------------------------------------------------------------------------------
Therefore, the first five terms of the partial sum is:
25.0000 + -37.5000 + 66.6667 + -63.5416 + 66.6667
savanah solved the equation 3+4 multiplied by the absolute value of x/2+3=11 for one solution. her work is shown below. what is the other solution to the given absolute value equation: savanah's solution was x= -2
Answer:
-10Step-by-step explanation:
Given the equation solved by savanah expressed as [tex]3+4|\frac{x}{2} + 3| = 11[/tex], IF she solved for one of the solution and got x = -2, we are to solve for the other value of x.
Note that the expression in modulus can be expressed as a positive expression and negative expression.
For the positive value of the expression [tex]|\frac{x}{2} + 3|[/tex] i.e [tex]\frac{x}{2} + 3[/tex], the expression becomes;
[tex]3+4(\frac{x}{2} + 3) = 11[/tex]
On simplification;
[tex]3+4(\frac{x}{2} + 3) = 11\\\\3 + 4(\frac{x}{2} )+4(3) = 11\\\\3 + \frac{4x}{2}+ 12 = 11\\\\3 + 2x+12 = 11\\\\2x+15 = 11\\\\Subtract \ 15 \ from \ both \ sides\\\\2x+15-15 = 11-15\\\\2x = -4\\\\x = -2[/tex]
For the negative value of the expression [tex]|\frac{x}{2} + 3|[/tex] i.e [tex]-(\frac{x}{2} + 3)[/tex], the expression becomes;
[tex]3+4[-(\frac{x}{2} + 3)] = 11[/tex]
On simplifying;
[tex]3+4[-(\frac{x}{2} + 3)] = 11\\\\3+4(-\frac{x}{2} - 3)= 11\\\\3-4(\frac{x}{2}) -12 = 11\\\\3 - \frac{4x}{2} - 12 = 11\\\\3 - 2x-12 = 11\\\\-2x-9 = 11\\\\add \ 9 \ to \ both \ sides\\\\-2x-9+9 = 11+9\\-2x = 20\\\\x = -20/2\\\\x = -10[/tex]
Hence her other solution of x is -10
Suppose you have read two different books on world war 2 and each book has different arguments about how the war started which of the following sources provides the best support for the authors arguments
Answer:
Well this is my opinion I would try to compared both them and see if they have something familiar in their arguments. If not I would try to view their different point of view and write your own opinion about it. I would check out another book about the World War 2 because there's infinite of books about it.
bananas cost $4 and apples close 0.60$ each if b represents the number of bunches of bananas and a represents the number of apple which of the following expressions represents the total cost? 1 4.60(b+a) 2 4b + 0.60 3 4.60 + a 4 4.60ab
Answer:
4b + .60a
Step-by-step explanation:
b represents the number of bunches of bananas
a represents the number of apple
Multiply the cost by the number purchased of each item and add them together
4b + .60a
Answer:
[tex]\huge\boxed{\$ (4 b + 0.60 a)}[/tex]
Step-by-step explanation:
Bananas represented by b
1 banana costs $4 so b bananas will cost $ 4 b
Apples represented by a
1 apples costs 0.60 $ so a apples will cost $ 0.60 a
Totally, they will cost:
=> $ (4 b + 0.60 a)
find out what's wrong with this graph
Answer:
The y-axis is upside down, meaning that instead of the values increasing as they go up, they decrease.
Solve the equation for solutions in the interval [0, 2 π). Use algebraic methods and give exact values. Support your solution graphically. cos2x = 0
Answer:
45° or 135°
Step-by-step explanation:
Cos 2x = 0
2x = cos^-1 0
2x = 90° or 270°
x= 45° or 135°
Answer:
Step-by-step explanation:
● cos 2x = 0
We khow that Pi/2 equals 0.
So
● 2x = Pi/2 or 2x= -Pi/2
Then:
● x = Pi/4 or x = -Pi/2
So the solutions are:
● x = Pi/4 + 2×k×Pi
● or x = -Pi/4 + 2×k×Pi
Where k is an integer
The picture below has a graphical solution
● Pi/4 is approximatively 0.785 and -Pi/4 is approximatively -0.785
● the output of both Pi/4 and -Pi/4 is 0
So our answer was righr
State the correct polar coordinate for the graph shown:
Answer:
Solution : ( - 8, - 5π/3 )
Step-by-step explanation:
There are four cases to consider here, the first two with respect to r > 0, the second two with respect to r < 0. For r < 0 we have the coordinates ( - 8, 60° ) and ( - 8, - 300° ) . - 300° in radians is - 5π/3, and hence our solution is option d. But let me expand on how to receive the coordinates. Again r is the directed distance from the pole, and theta is the directed angle from the positive x - axis.
So when r is either negative or positive, we can tell that this point is 8 units from the pole. Therefore - r = - 8 in both our second cases ( we are skipping the first two cases for simplicity ). For r < 0 the point will lay on the ray pointing in the opposite direction of the terminal side of theta.
Our first coordinate is ( - 8, 60° ). Theta will be 2 / 3rd of 90 degrees, or 60 degrees, for - r. Respectively the remaining degrees will be negative, 360 - 60 = 300, - 300. Our second point for - r will thus be ( - 8, - 300° ) . - 300° = - 5π/3 radians, and our coordinate will be ( - 8, - 5π/3 ).
point a is at (6,-6) and point c is at (-6, -2)
Find the cooridantes of point b on AC such that AB=3/4 AC
Answer:
(-3,-3)
B=(6-9,6+3)
in the diagram, find the values of a and b.
Answer:
m∠a = 67° , m∠b = 42°Step-by-step explanation:
∠a is alternate interior angle to ∠ECD
∠b is alternate interior angle to ∠BCD
so:
If AB || CD then:
m∠a = m∠ECD = 25° + 42° = 67°
m∠b = 42°
3 With 72 million bicycles, correct to the
nearest million, Japan is at the top of the list
of countries with most bicycles per person.
On average, Japanese people travel about
2 km by bicycle, correct to the nearest km,
each day. Calculate the upper bound for the
total distance travelled by all the bicycles in
Japan.
Answer:
181 million km
Step-by-step explanation:
"Correct to the nearest unit" means the actual value might be 1/2 unit larger (or smaller) than the reported value.
The upper bound would be the product of the maximum number of bicycles and the maximum distance each travels:
(72.5 · 10^6 bicycles)(2.5 km/bicycle) = 181.25 · 10^6 km
__
Since the given numbers are good to 2 significant figures (or so), we might reasonably put the upper bound as 180·10^6 km.
{4.OA.A.3} There are 1,492 chairs in the auditorium. Ms. Jones wants to put them into 10 rows. If she splits the chairs evenly into 10 rows, how many chairs will Ms. Jones have left over?
Answer:
2 chairs will be left over.
Step-by-step explanation:
Given that
There are a total of 1492 chairs.
which are to divided in 10 rows evenly.
To find:
Number of chairs left ?
Solution:
Let the number of chairs in each row = [tex]x[/tex]
There are 10 rows so number of chairs in rows = 10[tex]x[/tex]
Let the number of chairs left = [tex]y[/tex]
Total number of chairs =10[tex]x[/tex] + [tex]y[/tex] = 1492
The above equation is like:
Divisor [tex]\times[/tex] Quotient + Remainder = Dividend
So, we have to find the remainder in this question where we are given Divisor and Dividend.
10 [tex]\times[/tex] 149 + 2 = 1492
So, dividing 1492 with 10, we get remainder as 2.
Hence, 2 chairs will be left.
Solve for x (x+4)/3 = 2.
a. x = -2
b. x=2
c. x = 2/3
d. x= -10/3
Answer:
The answer is option BStep-by-step explanation:
[tex] \frac{x + 4}{3} = 2[/tex]
To solve it first of all cross multiply
That's
x + 4 = 6
Move 4 to the right side of the equation
The sign changes to negative
That's
x = 6 - 4
We have the final answer as
x = 2Hope this helps you
Consider population data with μ = 30 and σ = 3. (a) Compute the coefficient of variation. (b) Compute an 88.9% Chebyshev interval around the population mean. Lower Limit Upper Limit
Answer:
A. 10%
B. Lower limit= 21
Upper limit = 39
Step-by-step explanation:
Mean = 30
SD = 3
a. COV = SD/|x| × 100
= 3/30 × 100
= 10%
= 0.1
B. For 88.9 chevbychev interval:
= (1 - 1/K²) = 0.889
= 1/K² = 1 - 0.889
= 1/K² = 0.111
= K² = 1/0.111
= K² = 9
= K = √9
K = 3
Lower limit = 30 - 3(3)
Lower limit = 21
Upper limit = 30 + 3(3)
Upper limit = 39
Therefore lower limit is 21 and upper limit is 39
15 POINTS AND BRAINLIEST JUST HELP ME PLZZZZZ 4x^2 + 28x + 49 = 0 Rewrite equation (x + __ )^2 = __
Answer:
[tex]\boxed{(x+7)^2 =-3x^2-14x}[/tex]
Step-by-step explanation:
[tex]4x^2 + 28x + 49 = 0[/tex]
[tex]\sf Subtract \ 3x^2 \ and \ 14x \ from \ both \ sides.[/tex]
[tex]4x^2 + 28x + 49 -3x^2-14x= 0-3x^2-14x[/tex]
[tex]x^2 + 14x + 49 = -3x^2-14x[/tex]
[tex]\sf Factor \ left \ side \ of \ the \ equation.[/tex]
[tex](x+7)^2 =-3x^2-14x[/tex]
Answer:
(x+7)² = -3x² -14x
Step-by-step explanation:
4x^2 + 28x + 49 = 0
Subtract 3x² and 14x from each sides.
x^2 + 14x + 49 = -3x² -14x
Next step will be factoring.
(x+7)² = -3x² -14x
PLEASE HELP!
Suppose there is a strong positive correlation between mand n. Which of the
following must be true?
A. An increase in m causes n to increase.
B. When m increases, n tends to decrease.
C. When m increases, n tends to increase.
D. An increase in m causes n to decrease.
Answer:
A an increase in m cause n to increase
Step-by-step explanation:
a positive correlation means they will travel in the same direction when one is affected.
Answer:
Option A: An increase in m causes n to increase.
Step-by-step explanation:
A Positive correlation is a relationship between two variables in which both variables move with the same ratio. A positive correlation exists when one variable increases as the other variable increases, or vice-versa.
A perfect positive correlation means that both variables move by the exact same percentage.
Therefore, if there is a strong positive correlation between m and n then V increases and, w tends to increase.
Hope this helped :)
1.
The ratio of the numbers of sides of two regular polygons is 1:2 .If each interior angle of the first
polygon is 1200 then the measure of each interior angle of the second polygon
is
(1)1400
(2)1350
(3)1500
(4)1600
first polygon
ext. angle=180°-120°
=60°
[tex]ext \: ang = \frac{360}{n} [/tex]
n=360°/60°
n=6
second polygon
n=2(6)=12
ext. ang= 360°/n = 360°/12° = 30°
int. ang = 180°-30°= 150°
answer is C
If the ratio of the numbers of sides of two regular polygons is 1:2 and each interior angle of first angle is 120° then the measure of each interior angle of the second polygon is 150° which is option 3).
What is regular polygon?A regular polygon is a polygon whose all sides are equal to each other.
How to find interior angle?We have been given ratio of sides of two polygon that is 1:2 and the interior angle of first polygon that is 120 degrees.
Exterior angle will be 180-120=60°
We know that exterior angle =360/n where n is the sides of the polygon.
60=360/n
n=360/60
n=6
Number of sides of other polygon=2*6=12
Exterior angle=360/n
=360/12
=30
Interior angle=180-30=150°
Hence the interior angle of the second polygon is 150 degrees.
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A researcher reports a 98% confidence interval for the proportion of Drosophila in a population with mutation Adh-F to be [0.34, 0.38]. Therefore, there is a probability of 0.98 that the proportion of Drosophola with this mutation is between 0.34 and 0.38. True or False
Answer:
False
Step-by-step explanation:
The 98% is confidence interval its not a probability estimate. The probability will be different from the confidence interval. Confidence interval is about the population mean and is not calculated based on sample mean. Every confidence interval contains the sample mean. There is 98% confidence that the proportion of Drosophola with his mutation is between 0.34 and 0.38.
A man claims to have extrasensory perception (ESP). As a test, a fair coin is flipped10 times and the man is asked to predict the outcome in advance. He gets 7 out of10 correct. What is the probability that he would have done at least this well if hehad no ESP?
Answer:
I would say 70%
Step-by-step explanation:
He got 7 of of 10 (7/10 = 70%) right so I would say he would do just as well without ESP since it doesn't exist.
The first side of a triangle measures 3 in. less than the second side, the third side is 2 in. more than the first side, and the perimeter is 20 in. Set up an equation that relates the sides of the triangles in terms of the perimeter of the triangle.
Answer:
P = 3x - 4
Step-by-step explanation:
Side 1 = x - 3
Side 2 = x
Side 3 = 2 + (Side 1) = 2 + x - 3 = x - 1
Perimeter = 20 in
Perimeter = Side 1 + Side 2 + Side 3
Perimeter = (x - 3) + (x) + (x - 1)
Perimeter = x - 3 + x + x - 1
Perimeter = 3x - 3 - 1
Perimeter = 3x - 3 - 1
Perimeter = 3x - 4
P = 3x - 4
What is the lateral area of the drawing is it a 200 km.b. 425.c.114d.1021km
Answer:
114 km
Step-by-step explanation:
Each side is an isosceles trapezoid, so ED=2 since you would need to add 2 to each end of the bottom line to get the top line. Now use Pythagorean Theorem to get ED^2+AD^2=AE^2. Plug in your numbers to solve for AE. This is the height of each trapezoid. Then use your formula for the area of a trapezoid, (B1+B2)h/2, to get the area of each side, then multiply by 4 to get the lateral area since there are 4 sides. Remember lateral area is just the sides, then surface area is when you include the area of the two bases.
In rectangle ABCD, point E lies half way between sides AB and CD and halfway between sides AD and BC. If AB=10 and BC=2, what is the area of the shaded region? Answer as a decimal, if necessary. Little confused on this one.
Answer:
10 units²
Step-by-step explanation:
Consider the unshaded region to consists of 2 triangles, ∆AED and ∆BEC, which are both of equal dimensions. Their bases and heights are both the same. Both triangles are embedded inside a rectangle ABCD.
Area of the shaded region = Area of rectangle - area of the 2 triangles.
Area of rectangle = l*w
l = 10
w = 2
[tex] Area_R = 10*2 = 20 units^2 [/tex]
Area of the 2 triangles = 2(½*b*h)
b = 2
h = 5
[tex]Area_T = 2(\frac{1}{2}*2*5)[/tex]
[tex] Area_T = 1*2*5 = 10 units^2 [/tex]
Area of shaded region = 20 - 10 = 10 units²
A population consists of 100 elements. We want to draw a simple, random sample of 20 elements from this population. On the first selection, the probability of any particular element being selected is ____.
Answer:
1/5Step-by-step explanation:
Probability is the likelihood or chance that an event will occur.
Probability = expected outcome of event /total outcome
Since the population consists of 100 elements, the total outcome of event = 100.
If random sample of 20 element is drawn from the population, the expected outcome = 20
On the first selection, the probability of any particular element being selected = 20/100 = 1/5
A political candidate has asked his/her assistant to conduct a poll to determine the percentage of people in the community that supports him/her. If the candidate wants a 10% margin of error at a 95% confidence level, what size of sample is needed
Answer:
The desired sample size is 97.
Step-by-step explanation:
Assume that 50% people in the community that supports the political candidate.
It is provided that the candidate wants a 10% margin of error (MOE) at a 95% confidence level.
The confidence interval for the population proportion is:
[tex]CI=\hat p\pm z_{\alpha/2}\sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]
Then the margin of error is:
[tex]MOE= z_{\alpha/2}\sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]
Compute the critical value of z as follows:
[tex]z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96[/tex]
*Use a z-table.
Compute the sample size as follows:
[tex]MOE= z_{\alpha/2}\sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]
[tex]n=[\frac{z_{\alpha/2}\times \sqrt{\hat p(1-\hat p)} }{MOE}]^{2}[/tex]
[tex]=[\frac{1.96\times \sqrt{0.50(1-0.50)} }{0.10}^{2}\\\\=[9.8]^{2}\\\\=96.04\\\\\approx 97[/tex]
Thus, the desired sample size is 97.
