Using the z-distribution, it is found that she should take a sample of 97 scores to ensure that the margin of error is below 20.
What is a z-distribution confidence interval?The confidence interval is:
[tex]\overline{x} \pm z\frac{\sigma}{\sqrt{n}}[/tex]
In which:
[tex]\overline{x}[/tex] is the sample mean.z is the critical value.n is the sample size.[tex]\sigma[/tex] is the standard deviation for the population.The margin of error is given by:
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
Scores on the math portion of the SAT are believed to be normally distributed and range from 200 to 800, hence by the Empirical Rule the standard deviation is given by:
[tex]6\sigma = 800 - 200[/tex]
[tex]\sigma = 100[/tex]
In this problem, we have a 95% confidence level, hence[tex]\alpha = 0.95[/tex], z is the value of Z that has a p-value of [tex]\frac{1+0.95}{2} = 0.975[/tex], so the critical value is z = 1.96.
To ensure a margin of error of 20, we solve for n when M = 20, hence:
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
[tex]20 = 1.96\frac{100}{\sqrt{n}}[/tex]
[tex]20\sqrt{n} = 1.96 \times 100[/tex]
[tex]\sqrt{n} = 1.96 \times 5[/tex]
[tex](\sqrt{n})^2 = (1.96 \times 5)^2[/tex]
n = 96.04.
Rounding up, she should take a sample of 97 scores to ensure that the margin of error is below 20.
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Denise and Stacey went to a carnival. The admission fee was $6 per person. Each ride at the carnival costs c dollars. The game booths charged g dollars for each game. Both Denise and Stacey went on 7 rides each. Stacey played 3 games, while Denise played 2 games. Which expression represents the total amount of money that Denise and Stacey spent at the carnival?
The total amount of money that Denise and Stacey spent at the carnival is 12 + 14c + 5g dollars.
What is total amount?
The amount that you get when you add several numbers or things together.
The total amount of money that Denise and Stacey spent at the carnival will be money spent on admission + ride + game.
Total amount = 2 * 6 + 2 ( 7 * c ) + ( 3 * g + 2 * g )
= 2 * 6 + 14 * c + 5 * g
= 12 + 14c + 5g dollars.
Therefore, the total amount of money that Denise and Stacey spent at the carnival is 12 + 14c + 5g dollars.
The questions seems incomplete, its option could be:
12 + 14c + 5g 12 + 14g + 5c 12 + 7g + 5c 12 + 7c + 5g.
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What are the possible values of x in 8x² + 4x=-1? OA 2+1√2 3 -1±i 16 SOB. OC -1t с. 4 OD. 11 4 OE. 1ti√2 1+1/2 4 What are the possible values of x in 8x² + 4x = -1 ? OA 2 + 1√2 3 -1 ± i 16 SOB . OC -1t с . 4 OD . 11 4 OE . 1ti√2 1 + 1 / 2 4
Answer:
4
Step-by-step explanation:
4
The possible values of x are:
x = -1/2 + i/2
x = -1/2 - i/2
What is a quadratic equation?A basic quadratic equation, or a second-order polynomial equation with a single variable, is represented by the equation x : ax² + bx + c = 0, where a≠0 for the variable x. As it is a second-order polynomial equation, which is ensured by the algebraic fundamental theorem, it must have at least one solution.
To find the possible values of x in equation 8x² + 4x = -1, we need to solve for x.
First, we can rearrange the equation to get:
8x² + 4x + 1 = 0
We can solve this quadratic equation using the quadratic formula:
x = (-b ± √(b² - 4ac)) / 2a
where a, b, and c are the coefficients of the quadratic equation in standard form (ax² + bx + c).
In this case, a = 8, b = 4, and c = 1. Substituting these values into the quadratic formula, we get:
x = (-4 ± √(4² - 4(8)(1))) / 2(8)
x = (-4 ± √(16 - 32)) / 16
x = (-4 ± √(-16)) / 16
x = (-4 ± 4i) / 16
where i is the imaginary unit, which is defined as the square root of -1.
Therefore, the possible values of x are:
x = (-4 + 4i) / 16
x = (-4 - 4i) / 16
These values can also be simplified as:
x = -1/2 + i/2
x = -1/2 - i/2
So the possible values of x are complex numbers, specifically x = -1/2 ± i/2.
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A car travels at 80 km an hour. How far will it travel in 2 1/2 hours?
Find the value below using your calculator. Round to the nearest hundredth. e³ Find the value below using your calculator . Round to the nearest hundredth . e³
The value of e³ = 20.079.
What is Euler's number , e ?e is an irrational number , It is a numerical constant used in mathematical constant .
The value of e = 2.718
It is asked in the question to determine the value of e³
Therefore
e³ = ( 2.718)³
e³ = 20.079
Therefore the value of e³ = 20.079.
The image of the calculation is attached with the answer.
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If f(n)= n²-n, then f(-4) is
O-20
12
-12
20
Answer: 20
Step-by-step explanation:
f(-4) = -4² - (-4)
f(-4) = 16 + 4
f(-4) = 20
Solve (X+8)=9 absolute value equation PLEASE HELP
Answer:
x = | 1 |
Step-by-step explanation:
how are u in college doing this???
Answer:
1
Step-by-step explanation:
(x+8)=9
x+8=9
x=9-8
x=1
Can somebody help me
Step-by-step explanation:
first function, f(x) = 5x-3 goes with option B
2nd function, 4- 4x goes with option A
3rd function goes with option D
4th goes with option C
PLEASE HELP ASAP PLEASEEEEEEE PLEASEEEEEEEEE EASY 20 POINTS
The transformation of a function may involve any change. The function with the graph are given below.
How does the transformation of a function happen?The transformation of a function may involve any change.
Usually, these can be shifted horizontally (by transforming inputs) or vertically (by transforming output), stretched (multiplying outputs or inputs) etc.
If the original function is y = f(x), assuming horizontal axis is input axis and vertical is for outputs, then:
Horizontal shift (also called phase shift):
Left shift by c units: y=f(x+c) (same output, but c units earlier)Right shift by c units: y=f(x-c)(same output, but c units late)Vertical shift:
Up by d units: y = f(x) + dDown by d units: y = f(x) - dStretching:
Vertical stretch by a factor k: y = k \times f(x)Horizontal stretch by a factor k: y = f\left(\dfrac{x}{k}\right)The real graph of the function is f(x)=x², now if the graph of the given function can be found by using the transformation rule as shown above. The function with the graph are given below.
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Find the solutions to x² = 8.
A. x- +4√6
B. x- +4√√2
C. x=+2√4
D. x=+2√2
Answer:
D. 2√2
Step-by-step explanation:
x² = 8
x = √8
x = √4 x √2
x = 2√2
Step-by-step explanation:
[tex] x {?}^{2} \sqrt{2 \times 2 \times 2} \\ \\ x { }^{2} = 2 \sqrt{2} [/tex]
42+48/6=?
48/6 meaning a fraction not division
Answer:
50
Step-by-step explanation:
Fractions are division problems. :) You have to complete that first to solve the equation (PEMDAS).
48/6 = 8
42 + 8 = 50
Which is the graph of 2x - 4y > 6?
-4 -2
2
-2
2
RUTA
4-2
414
2
O
W
4 -4-2
414
2
-2
O
2
RY
4
-2
2
211
Answer:
(d) see attached
Step-by-step explanation:
There are a couple of quick checks you can do to identify the correct graph.
__
shading and line styleFind a variable with a positive coefficient, and write that in the given relation to the inequality symbol:
x >
This tells you ...
shading is to the right of the line (where x-values are greater)the line is dashed (the = case is not included)location of the lineThe x-coefficient is a factor of the constant, so the x-intercept of the boundary line is easily found. Set y=0, and you have ...
2x = 6
x = 3
The boundary line you're looking for has an x-intercept at x=3.
__
The correct graph is shown in the attachment.
which relation describes the graph?
Answer:
A.
Step-by-step explanation:
The other graphs answers have a point at (3, 1) which is not on the graph.
Need help please answer!!!
It can be modeled by an exponential function because each time x increases by 1, f(x) is multiplied by 4.
This means the base of the exponential function is 4, and since f(x)=3 when x=0, [tex]f(x)=3(4)^{x}[/tex]
I need helpppppp asap
Answer:
graph A
Step-by-step explanation:
When looking at a graph, there are two different axes. The vertical values--marked by the center up/down line--are "y-values"; and this is called the "y-axis"
The horizontal values--marked by the left/right line--are "x-values"; and this is called the "x-axis"
For the x-axis, values to the left side of the origin (the place where the y-axis and x-axis intercept) are smaller than 0--they are all negative values.
Values to the right side of the origin are positive--greater than 0.
For the y-axis, positive numbers are on the top half [once again, the midpoint / 0 is where the two lines are both = to 0; the origin] and negative numbers are on the bottom half.
Ordered pairs (points) are written as (x,y)
(x-value, y-value)
We are looking for a graph that decreases (along the y-axis), hits a point below the origin, and goes flat/stays constant.
When a graph is decreasing (note: we read graphs from left to right), the line of the graph is slanted downwards (it looks like a line going down).
So, if we look at the graphs, we can see Graph A descending, crossing the y-axis {crossing the middle line /vertical line / y-axis} at a value of -7, and then staying constant (it is no longer increasing or decreasing because the y-values stay the same)
hope this helps!!
Pls help why did she flip the sign i dont understand
Answer:
See below
Step-by-step explanation:
When you multiply or divide both sides of an inquality equation by a NEGATIVE number , it reverses the symbol to see this in action:
- 4n >36 Instead of dividing by -4 let's ADD - 4n to both sides
0 > 36 + 4n now SUBTRACT 36 from both sides
-36 > 4n re-arrange just a little
4n < -36 <======== see how the symbol has reversed ???
n < -9
Hii!
___________________________________________________________
Answer:
'Cause both sides were divided by a negative number! ^^
Step-by-step explanation:
The sign of the inequality was flipped because you divided both sides of the inequality by -4, which is a negative number.
When we divide, or multiply, both sides of an inequality by a negative number, we flip the inequality sign.
--
Hope that this helped! Best wishes.
--
twice a number increased by 8 is 20. find the number
Answer:
Answer is 6
Step-by-step explanation:
Let the number be ×
Twice a number is 2×
Twice a number increase by 8 is 2×+8
hence the equivalent will be
2×+8=20
2×=12
×6
Answer:
6
Step-by-step explanation:
Let n be the unknown number.
"Twice a number" means to multiply the number by 2:
⇒ 2n
"Increase by 8" means to add 8:
⇒ 2n + 8
"Is 20" means equals 20:
⇒ 2n + 8 = 20
Therefore, the equation is: 2n + 8 = 20
To solve, subtract 8 from both sides:
⇒ 2n + 8 - 8 = 20 - 8
⇒ 2n = 12
Divide both sides by 2:
⇒ 2n ÷ 2 = 12 ÷ 2
⇒ n = 6
Therefore, the unknown number is 6.
Katie divided a drink with a volume
of 3½ cups into ½ cup servings.
How many servings did she have?
Answer:
Step-by-step explanation:
she has 7 servings. Add 1/2 + 1/2 until you get 3 1/2 and it equals 7
What is the solution to this equation? 2ln4+lnx=3ln2+ln(x+1)
Answer:
[tex]x=1[/tex]
Step-by-step explanation:
Given equation:
[tex]2 \ln 4+\ln x=3 \ln 2+\ln(x+1)[/tex]
[tex]\textsf{Apply the power law}: \quad n \ln x = \ln x^n[/tex]
[tex]\implies \ln 4^2+\ln x=\ln 2^3+\ln(x+1)[/tex]
Simplify:
[tex]\implies \ln 16+\ln x=\ln 8+\ln(x+1)[/tex]
Subtract ln 8 from both sides:
[tex]\implies \ln 16+\ln x- \ln 8=\ln(x+1)[/tex]
Subtract ln x from both sides:
[tex]\implies \ln 16-\ln 8=\ln(x+1)-\ln x[/tex]
[tex]\textsf{Apply the quotient law}: \quad \ln x - \ln y = \ln \frac{x}{y}[/tex]
[tex]\implies \ln \left\dfrac{16}{8}\right = \ln \left(\dfrac{x+1}{x}\right)[/tex]
Simplify:
[tex]\implies \ln 2 = \ln \left(\dfrac{x+1}{x}\right)[/tex]
[tex]\textsf{Apply the equality law}: \quad \textsf{if }\: \ln x= \ln y\:\textsf{ then }\:x=y[/tex]
[tex]\implies 2=\dfrac{x+1}{x}[/tex]
Multiply both sides by x:
[tex]\implies 2x=x+1[/tex]
Subtract x from both sides:
[tex]\implies x=1[/tex]
Genesis throws a ball up in the air. The graph below shows the height of the ball hh in meters after tt seconds. Find the interval for which the ball’s height is decreasing.
help please
We conclude that the interval in which the function decreases is (1.5, 3]
In which interval is the ball's height decreasing?
The ball is decreasing when the graph, reading from left to right, is going downwards.
Particularly, in this parabola that opens downwards, the graph will decrease after the vertex.
And we can see that the vertex is at x = 1.5
And we also see that the graph of the function ends at x = 3.
Then we conclude that the interval in which the function decreases is (1.5, 3]
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Christina knits a scarf for each of her 7 friends. Altogether, the scarfs had a total length of 39.9 ft. if each scarf has the same length. how long was each scarf? write answer in inches
The length of each scarf knitted for the 7 friends given the total length of the scarf altogether is 5.7 ft
Length of each scarfNumber of friends = 7Total length of scarf = 39.9 ftLength of each scarf = Total length of scarf / Number of friends
= 39.9 ft / 7
= 5.7 ft
Therefore, the length of each scarf knitted for the 7 friends given the total length of the scarf altogether is 5.7 ft
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Solve for x in the triangle. Round your answer to the nearest tenth.
14
x
68
X
Answer:
x=15.1
Step-by-step explanation:
Side definitionsIn a right triangle, the side across from the right angle is always the hypotenuse.
The other two sides are termed "legs".
Once one of the other two angles is chosen as the angle to work from, then the two legs can be defined as the "opposite" and the "adjacent"
The leg touching the angle is the "adjacent" leg (or adjacent side), and the leg across from the angle is the "opposite" leg (or opposite side).
Trigonometric function definitions[tex]\sin(\theta)=\dfrac{\text{opposite side}}{\text{hypotenuse}}[/tex]
[tex]\cos(\theta)=\dfrac{\text{adjacent side}}{\text{hypotenuse}}[/tex]
[tex]\tan(\theta)=\dfrac{\text{opposite side}}{\text{adjacent side}}[/tex]
In this situation, the given angle is in the bottom right. A value is given for the side opposite the given angle, and the requested value is on the hypotenuse.
So, the two sides of interest are the "opposite" and the "hypotenuse". The trigonometric function that relates these two sides is the sine function.
Calculating x[tex]\sin(\theta)=\dfrac{\text{opposite side}}{\text{hypotenuse}}[/tex]
[tex]\sin(68^o)=\dfrac{(14)}{(x)}[/tex]
Evaluating the sine function in a calculator (in degree mode):
[tex]0.9271838546...=\dfrac{14}{x}[/tex]
Multiply both sides by x:
[tex](0.9271838546...)x=\left (\dfrac{14}{x} \right)x[/tex]
[tex](0.9271838546...)x=14[/tex]
Divide both sides by the decimal number:
[tex]\left (\dfrac{(0.9271838546...)x}{0.9271838546...} \right)=\dfrac{14}{0.9271838546...}[/tex]
[tex]x=15.0994864...[/tex]
Rounded to the nearest tenth, x=15.1
Question 2 of 11
What system of equations would you use to solve the problem below?
A test is worth 100 points. Multiple-choice questions are worth 3 points and
short-answer questions are worth 5 points. If the test has 28 questions, how
many multiple-choice questions are there?
If the number of multiple-choice questions is x and the number of short answer questions is y, then:
[tex]x+y=28\\\\3x+5y=100[/tex]
pls someone help me asap
Answer:
Area: 15.53 square inches
Perimeter: 15.71 inches
Step-by-step explanation:
Area:
So the area of the rectangle is pretty easy to find and is just the width * height. In this case it's 4 * 3 which is 12. Now the area of a circle is [tex]\pi r^2[/tex]. But since this is a semi circle it's half of that which is [tex]\frac{\pi r^2}{2}[/tex]. The diameter of the semicircle is 3 as it sits on top of the rectangle. The radius is half of the diameter so the radius is 1.5. Now plug that into the equation and you get [tex]\frac{(3.14) (1.5)^2}{2} = 3.5325[/tex]. Now add that to 12 and you get 15.5325. Round that number to the nearest hundredth and you get 15.53. So that's the area.
Perimeter:
Pi is the ratio of any circle's circumference to the diameter. Or in other words the circumference is equal to the diameter * 3.14. The diameter is 3 which you multiply by 3.14 to get the circumference of a circle. This will get you 9.42 but since it's a semicircle, the circumference is half of this value which is 4.71. The perimeter of the rectangle is just 2 times the width + 2 times the height. This is not completely the case in this shape since one of the sides of the rectangle is not a side of the two shapes joined together. Which is the side that is parallel to the side of length 3 inches. So the perimeter is going to be 2(4) + 3. This gives you 11 which you add to the 4.71 and get 15.71
Please help it is 10th grade Equations of lines and circles 7. Michael is hanging out in the park and needs to keep his so
a. If Michael is standing at the coordinate (5, 2), and each unit represents a foot, what
equation could be used to show the proper social distance needed?
-6-5 -3-2
12 3456
b. If Jake is standing on the coordinate (1, 1), are the two friends properly distanced?
2
45
Step-by-step explanation:
1) the required equation in common form is:
(x-x₀)²+(y-y₀)²=r², where (x₀;y₀) - coordinates, where Michael is standing; r - the social distance;
According to the common form and given coordinates (x₀=-5; y₀=2; r=6) it is possible to make up the required equation:
(x+5)²+(y-2)²=6².
2) if the distance between two friends is:
[tex]d=\sqrt{(-5-1)^2+(2-1)^2}=\sqrt{37}, \ then[/tex]
this distance is longer than social (6 ft). For more info see the attachment.
find the x intercepts of the following linear function 3x-5y=-15
Answer:
(-5, 0)
Step-by-step explanation:
The y value of an x intercept is always 0. Therefore, we can substitute 0 for y in the equation to find the x intercept:
3x - 5(0) = -15
3x = -15
x = -5
The x intercept is (-5, 0)
Select the correct answer. Consider this function. Which graph represents the inverse of function f? The linear function on a coordinate plane passes through (4, 3), and (2, 2) which intercepts the axis at (0, 1), and (minus 2, 0). W. The linear function on a coordinate plane passes through (minus 4, 4), and (2, 1) which intercepts the axis at (4, 0), and (0, 2). X. The linear function on a coordinate plane passes through (3, 4), and (minus 1, minus 4) which intercepts the axis at (1, 0), and (0, minus 2). Y. The linear function on a coordinate plane passes through (minus 1, 4), and (2, minus 2) which intercepts the axis at (0, 2), and (0, 1). Z. A. W B. X C. Z D. Y
Answer:
A , C , D , i thinks it another one but ionk
Step-by-step explanation:
A pattern has 38 black squares to every 24 red squares. What is the ratio of black squares to red squares?
Step-by-step explanation:
the answer is 38/24 so the final answer is 19/12
1) Suppose the heights of 18-year-old men are approximately normally distributed, with mean 71 inches and standard deviation 5 inches.
a)
What is the probability that an 18-year-old man selected at random is between 70 and 72 inches tall? (Round your answer to four decimal places.)
b)
If a random sample of twenty-six 18-year-old men is selected, what is the probability that the mean height x is between 70 and 72 inches? (Round your answer to four decimal places.)
c)
Compare your answers to parts (a) and (b). Is the probability in part (b) much higher? Why would you expect this?
!) The probability in part (b) is much higher because the mean is larger for the x distribution.
!!) The probability in part (b) is much lower because the standard deviation is smaller for the x distribution.
!!!) The probability in part (b) is much higher because the standard deviation is smaller for the x distribution.
!!!!) The probability in part (b) is much higher because the mean is smaller for the x distribution.
!!!!!) The probability in part (b) is much higher because the standard deviation is larger for the x distribution.
2) Let x be a random variable that represents the level of glucose in the blood (milligrams per deciliter of blood) after a 12 hour fast. Assume that for people under 50 years old, x has a distribution that is approximately normal, with mean = 66 and estimated standard deviation = 45. A test result x < 40 is an indication of severe excess insulin, and medication is usually prescribed.
a)
What is the probability that, on a single test, x < 40? (Round your answer to four decimal places.)
b)
Suppose a doctor uses the average x for two tests taken about a week apart. What can we say about the probability distribution of x? Hint: See Theorem 6.1.
!) The probability distribution of x is approximately normal with x = 66 and x = 45.
!!) The probability distribution of x is approximately normal with x = 66 and x = 22.50.
!!!) The probability distribution of x is approximately normal with x = 66 and x = 31.82.
!!!!) The probability distribution of x is not normal.
c) What is the probability that x < 40? (Round your answer to four decimal places.)
d) Repeat part (b) for n = 3 tests taken a week apart. (Round your answer to four decimal places.)
e) Repeat part (b) for n = 5 tests taken a week apart. (Round your answer to four decimal places.)
f) Compare your answers to parts (a), (b), (c), and (d). Did the probabilities decrease as n increased?
Yes
NO
g) Explain what this might imply if you were a doctor or a nurse.
!) The more tests a patient completes, the weaker is the evidence for lack of insulin.
!!) The more tests a patient completes, the stronger is the evidence for lack of insulin.
!!!) The more tests a patient completes, the weaker is the evidence for excess insulin.
!!!!) The more tests a patient completes, the stronger is the evidence for excess insulin.
Answer:
Suppose the heights of 18-year-old men are approximately normally distributed, with mean 71 inches and standard deviation 4 inches.
(a) What is the probability that an 18-year-old man selected at random is between 70 and 72 inches tall? (Round your answer to four decimal places.)
z1 = (70-71)/4 = -0.25
z2 = (72-71/4 = 0.25
P(70<X<72) = p(-0.25<z<0.25) = 0.1974
Answer: 0.1974
(b) If a random sample of thirteen 18-year-old men is selected, what is the probability that the mean height x is between 70 and 72 inches? (Round your answer to four decimal places.)
z1 = (70-71)/(4/sqrt(13)) = -0.9014
z2 = (72-71/(4/sqrt(13)) = 0.9014
P(70<X<72) = p(-0.9014<z<0.9014) = 0.6326
Answer: 0.6326
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one phone company charged 65% of its normal long-distance rate after 5 p.m. A day-rate long-distance call from Houston to Chicago costs 20 cents per minute. How much is an 11-minute call between these two cities after 5 p.m. ?
The cost of 11-minute call between these two cities after 5 p.m is: 142.
CostGiven:
Charges for long distance=65% or .65
Cost=20 cents per minutes
Number of call minutes=11 minutes
Hence:
Cost =20 cents ×11 minutes times 0.65
Cost =143 cents
Therefore the cost of 11-minute call between these two cities after 5 p.m is: 142.
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Tim earns 96pounds for 16 hours. Tim earns 'time and a half' for overtime. he works 4 hours of overtime in addition to his normal 16 hours. how much does he earn altogether
find hourly rate:
96 / 16 = 6 pounds per hour
6 x 1.5 = 9 pounds per hour for overtime.
9 x 4 = 36 pounds
96 + 36 = 132 pounds total