The question is incomplete. The complete question is :
An automobile assembly line operation has a scheduled mean completion time, μ, of 15.5 minutes. The standard deviation of completion times is 1.7 minutes. It is claimed that, under new management, the mean completion time has decreased. To test this claim, a random sample of 90 completion times under new management was taken. The sample had a mean of 15.4 minutes. Can we support, at the 0.1 level of significance, the claim that the mean completion time has decreased under new management?
Solution :
The given data :
n = 90
μ = 15.5
σ = 1.7
[tex]$\overline x$[/tex] = 15.4
So, the null hypothesis is : [tex]$H_0: \mu = 15.5$[/tex] is been tested against
Alternate hypothesis : [tex]$H_1 : \mu < 15.5 $[/tex] (one-tailed test)
Since, the sample size is sufficiently large and the sample deviation is known, we use the Z-test.
Under this test, the test statistic is given as :
[tex]$Z=\frac{\overline x - \mu}{\sigma/\sqrt{n}} \sim N(0,1)$[/tex]
Under [tex]H_0[/tex], we have
[tex]$Z_0=\frac{\overline x - \mu}{\sigma/\sqrt{n}} $[/tex]
[tex]$Z_0=\frac{15.4-15.5}{1.7/\sqrt{90}} $[/tex]
[tex]$Z_0=-0.56$[/tex]
The critical value for the test is [tex]$Z_{\alpha} = Z_{0.1} = -1.28$[/tex]
We observe that (-0.56 > -1.28), and so we fail to reject the null hypothesis.
No, there is no evidence to support the claim that the mean completion time has decreased.
Thus, we conclude that the mean completion time is 15.5 minutes.
the first four terms of a sequence are shown below:
7,4,1,-2
which of the following functions best defines this sequence?
A) f(1)=7, f(n+1)= f(n)+3; for n>= 1
B) f(1)=7, f(n+1)= f(n)-3; for n >= 1
C) f(1)=7, f(n+1)= f(n)-4; for n >= 1
D) f(1)=7, f(n+1)= f(n)+4; for n >= 1
9514 1404 393
Answer:
B) f(1)=7, f(n+1)= f(n)-3; for n >= 1
Step-by-step explanation:
The first term of the sequence is 7 and the next (4) is found by adding -3 to that: 4 = 7-3. This is described in answer choice B.
I need help please. Show work
Answer:
28
Step-by-step explanation:
10/14 mph no wind
20 wind
14 x 2 = 28
28 mph with wind
B
15x+7
6x+2y|
y +3
2y + 1
С
E
The triangles are congruent. Find the length of each hypotenuse.
A. 3
B. 5
C 17
Answer:
Hypothenus = 22
Step-by-step explanation:
From the question given above, we were told that the triangles are congruent (i.e same size). Thus,
AC = EF
BC = DE
To obtain the length of each Hypothenus, we shall determine the value of y and x. This can be obtained as follow:
For y:
AC = y + 3
EF = 2y + 1
AC = EF
y + 3 = 2y + 1
Collect like terms
3 – 1 = 2y – y
2 = y
y = 2
For x:
BC = 5x + 7
DE = 6x + 2y
y = 2
DE = 6x + 2(2)
DE = 6x + 4
BC = DE
5x + 7 = 6x + 4
Collect like terms
7 – 4 = 6x – 5x
3 = x
x = 3
Finally, we shall determine the length of each Hypothenus. This can be obtained as follow:
Hypothenus = BC
Hypothenus = 5x + 7
x = 3
Hypothenus = 5x + 7
Hypothenus = 5(3) + 7
Hypothenus = 15 + 7
Hypothenus = 22
OR
Hypothenus = DE
DE = 6x + 2y
y = 2
x = 3
Hypothenus = 6(3) + 2(2)
Hypothenus = 18 + 4
Hypothenus = 22
Shirley has a collection of 50 stamps and adds 4 stamps daily to her collection. Model this situation as a function of number of days (d).
Answer:
N = 50 +4d
Step-by-step explanation:
Take the original number of stamps and add the stamps per days times the number of days
N = 50 +4d
4. Write the number 3.8 in the form using integers, to show that it is a rational number. 8 11 38 10 10 38 100
Answer:
38 divided by 10 equals 3.8
Use calculus to find the absolute maximum and minimum values of the function. f(x) = 5x − 10 cos(x), −2 ≤ x ≤ 0 (a) Use a graph to find the absolute maximum and minimum values of the function to two decimal places.
Answer:
gkg8fyaueajrkvxogogzoggkdggkdyyskyyeykektkykyksskysysskkyky
Answer:
The absolute maximum is about -5.84 at x = -2.
And the absolute minimum is about -11.28 at x = -π/6.
Step-by-step explanation:
We want to find the absolute maximum and minimum values of the function:
[tex]\displaystyle f(x) = 5x-10\cos x\text{ for } -2\leq x\leq 0[/tex]
First, we should evaluate the endpoints of the interval:
[tex]\displaystyle f(-2) = 5(-2) - 10\cos (-2) \approx -5.8385[/tex]
And:
[tex]f(0) = 5(0) -10\cos (0) = -10[/tex]
Recall that extrema of a function occurs at its critical points. The critical points of a function are whenever its derivative is zero or undefined.
So, find the derivative of the function:
[tex]\displaystyle f'(x) = \frac{d}{dx}\left[ 5x - 10\cos x\right][/tex]
Differentiate:
[tex]\displaystyle f'(x) = 5 + 10\sin x[/tex]
Set the function equal to zero:
[tex]\displaystyle 0 = 5+10\sin x[/tex]
And solve for x:
[tex]\displaystyle \sin x = -\frac{1}{2}[/tex]
Using the unit circle, our solutions are:
[tex]\displaystyle x = \frac{7\pi}{6} + 2n\pi\text{ or } \frac{11\pi}{6} + 2n\pi \text{ where } n\in \mathbb{Z}[/tex]
There is only one solution in the interval [-2, 0]:
[tex]\displaystyle x = \frac{11\pi}{6} - 2\pi = -\frac{\pi}{6}\approx -0.5236[/tex]
Thus, we only have one critical point on the interval.
Substituting this back into the function yields:
[tex]\displaystyle\begin{aligned} f\left(-\frac{\pi}{6}\right) &= 5\left(-\frac{\pi}{6}\right) - 10\cos \left(-\frac{\pi}{6}\right) \\ \\ &=-\frac{5\pi}{6} - 5\sqrt{3}\\ \\ &\approx -11.2782 \end{aligned}[/tex]
In conclusion, the absolute maximum value of f on the interval [-2, 0] is about -5.8385 at x = -2 and the absolute minimum value of f is about -11.2782 at x = -π/6.
We can see this from the graph below as well.
Hi can someone answer this question please thank you
Answer:
25
Step-by-step explanation:
5:20
We want to get the second number to 100
100/20 = 5
Multiply each term by 5
5*5 : 20*5
25 : 100
x is 25
Given that,
→ 5 : 20 :: x : 100
Then we have to,
find the second number to 100.
→ 100/20
→ 5
Now multiply each term by 5 in 5:20,
→ 5 × 5 : 20 × 5
→ 25 : 100
→ x = 25
Now these ratio will be,
→ 5 : 20 :: 25 : 100
Hence, the value of x is 25.
Choose ALL of the following functions that represent exponential decay. f(x) = 5(2/3)^x
Answer:
exponential decay
Step-by-step explanation:
The function is in the form
y = ab^x where a is the initial value and b is the growth or decay rate
If b >1 then it is growth
b < 1 then it is decay
f(x) = 5(2/3)^x
a = 5
b = 2/3
2/3 <1 so it is decay
A store offers packing and mailing services to customers. The cost of shipping a box is a combination of a flat packing fee of $5 and an amount based on the weight in pounds of the box, $2.25 per pound. Which equation represents the shipping cost as a function of x, the weight in pounds?
f(x) = 2.25x + 5
f(x) = 5x + 2.25
f(x) = 2.25x − 5
f(x) = 5x − 2.25
Answer:
f(x) = 2.25x + 5
Step-by-step explanation:
The cost from the weight in pounds of the box can be represented by 2.25x, since the charge is $2.25 per pound.
The flat fee of $5 can be represented in the function by adding 5 to 2.25x.
Put these together in function notation:
f(x) = 2.25x + 5
So, the equation is f(x) = 2.25x + 5
I’m new and i need help!!
Please help me of you know the answers.
Answer:
2, x, 2x
Step-by-step explanation:
A) 2
They are even numbers, so it is going to be 2.
B) x
It is going to only be x because the exponents are even and odd.
C) 2x
It is going to be 2x because the numbers are even but the exponents are even and odd.
Hope this helps.
What is the circumference of the circle in terms of [tex]\pi[/tex]?
a. 900[tex]\pi[/tex] in.
b. 90[tex]\pi[/tex] in.
c. 60[tex]\pi[/tex] in.
d. 30[tex]\pi[/tex] in.
Answer:
[tex]c. \: 60\pi \: in.[/tex]Step-by-step explanation:
Given,
Radius = 30 in
So,
Circumference
[tex] = 2\pi r[/tex]
[tex] = 2 \times \pi \times 30in.[/tex]
[tex] = 60\pi \: in.(ans)[/tex]
[tex] \sf \: r \: = 30 \: in. \\ \sf \: C \: = 2\pi r \\ \\ \sf \: C \: = 2\pi(30) \\ \sf \: C = 2 \times 30\pi \\ \sf \: C = \boxed{\underline{ \bf c. \: 60\pi \: in.}}[/tex]
Enter the correct answer in the box.
Simplify the expression x^5•x^7
Answer:
[tex]x^{7}[/tex]
Step-by-step explanation:
When multiplying exponents, you add them together.
x^12
Step-by-step explanation:
x^5*x^7
x^5+7
=x^12
It cost $52 to use 800 kWh of electricity. How much will 650 kWh cost?
Hello!
$52 ..... 800kWh
$x ..... 650kWh
_____________
52/x = 800/650 <=>
<=> 52 × 650 = 800x <=>
<=> 33800 = 800x <=>
<=> 800x = 33800 <=>
<=> x = 33800/800 <=>
<=> x = 338/8 <=>
<=> x = 169/4 <=>
<=> x = 42,25$
Good luck! :)
On a coordinate plane, rhombus W X Y Z has points (negative 3, 1), (1, 4), (5, 1), and (1, negative 2). Rhombus WXYZ is graphed on a coordinate plane. What is the area of the rhombus?
Answer:
B. 20 Units
Step-by-step explanation:
unit test review edge 2021
The area of rhombus WXYZ as shown in the diagram given with the given vertices is: 24 units².
What is the Area of a Rhombus?Area of a rhombus = pq/2, where p and q are the diagonals of the rhombus.
Find the lengths of diagonals XZ and WY:
XZ = |4 -(-2)| = 6 units
WY = |-3 - 5| = 8 units
Area of rhombus WXYZ = 1/2(XZ × WY) = 1/2(6 × 8)
Area of rhombus WXYZ = 24 units².
Learn more about the area of a rhombus on:
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An experiment to investigate the survival time in hours of an electronic component consists of placing the parts in a test cell and running them under elevated temperature conditions. Six samples were tested with the following resulting failure times (in hours): 34, 40, 46, 49, 61, 64. (a)Calculate the sample mean and sample standard deviation of the failure time. (b)Determine the range of the true mean at 90% confidence level. (c)If a seventh sample is tested, what is the prediction interval (90% confidence level) of its failure time
Answer:
a) The sample mean is of 49 and the sample standard deviation is of 11.7.
b) The range of the true mean at 90% confidence level is of 9.62 hours.
c) The prediction interval, at a 90% confidence level, of it's failure time is between 39.38 hours and 58.62 hours.
Step-by-step explanation:
Question a:
Sample mean:
[tex]\overline{x} = \frac{34+40+46+49+61+64}{6} = 49[/tex]
Sample standard deviation:
[tex]s = sqrt{\frac{(34-49)^2+(40-49)^2+(46-49)^2+(49-49)^2+(61-49)^2+(64-49)^2}{5}} = 11.7[/tex]
The sample mean is of 49 and the sample standard deviation is of 11.7.
b)Determine the range of the true mean at 90% confidence level.
We have to find the margin of error of the confidence interval. Since we have the standard deviation for the sample, the t-distribution is used.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 6 - 1 = 5
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 5 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.0.150
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}}[/tex]
In which s is the standard deviation of the sample and n is the size of the sample. So
[tex]M = 2.0150\frac{11.7}{\sqrt{6}} = 9.62[/tex]
The range of the true mean at 90% confidence level is of 9.62 hours.
(c)If a seventh sample is tested, what is the prediction interval (90% confidence level) of its failure time.
This is the confidence interval, so:
The lower end of the interval is the sample mean subtracted by M. So it is 49 - 9.62 = 39.38 hours.
The upper end of the interval is the sample mean added to M. So it is 49 + 9.62 = 58.62 hours.
The prediction interval, at a 90% confidence level, of it's failure time is between 39.38 hours and 58.62 hours.
A psychologist suspects that heroin addicts have a different assessment of self-worth than others in the general population. On a test designed to measure self-worth, the mean for the general population is 48.6. The psychologist obtains a random sample of 40 test scores produced by heroin addicts and found the sample mean and the sample standard deviations are 45.5 and 8.5, respectively. Do these data indicate the self-worth of heroin addicts is less than that of the general population?
Answer:
The p-value of the test if 0.0131, which is less than the standard significance level of 0.05, meaning that these data indicates that the self-worth of heroin addicts is less than that of the general population.
Step-by-step explanation:
On a test designed to measure self-worth, the mean for the general population is 48.6.
At the null hypothesis, we test if the mean is of 48.6, that is:
[tex]H_0: \mu = 48.6[/tex]
A psychologist suspects that heroin addicts have a different assessment of self-worth than others in the general population. Test if it is lower.
At the alternative hypothesis, we test if the mean is lower, that is:
[tex]H_1: \mu < 48.6[/tex]
The test statistic is:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, s is the standard deviation and n is the size of the sample.
48.6 is tested at the null hypothesis:
This means that [tex]\mu = 48.6[/tex]
The psychologist obtains a random sample of 40 test scores produced by heroin addicts and found the sample mean and the sample standard deviations are 45.5 and 8.5, respectively.
This means that [tex]n = 40, X = 45.5, s = 8.5[/tex]
Value of the test statistic:
[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]
[tex]t = \frac{45.5 - 48.6}{\frac{8.5}{\sqrt{40}}}[/tex]
[tex]t = -2.31[/tex]
P-value of the test:
The p-value of the test is a one-tailed test(mean lower than a value), with t = -2.31 and 40 - 1 = 39 df.
Using a t-distribution calculator, this p-value is of 0.0131.
The p-value of the test if 0.0131, which is less than the standard significance level of 0.05, meaning that these data indicates that the self-worth of heroin addicts is less than that of the general population.
find the differential equation of this function and indicate the order y = e^3x (acos3x +bsin3x)
Answer:
y"-6y'+18y=0
Second order
Step-by-step explanation:
Since there are 2 constants, the order of the differential equation will be 2. This means we will need to differentiate twice.
y = e^(3x) (acos3x +bsin3x)
y'=3e^(3x) (acos3x+bsin3x)
+e^(3x) (-3asin3x+3bcos3x)
Simplifying a bit by reordering and regrouping:
y'=e^(3x) cos3x (3a+3b)+e^(3x) sin3x (3b-3a)
y"=
3e^(3x) cos3x (3a+3b)+-3e^(3x) sin(3x) (3a+3b)
+3e^(3x) sin3x (3b-3a)+3e^(3x) cos(3x) (3b-3a)
Simplifying a bit by reordering and regrouping:
y"=
e^(3x) cos3x (9a+9b+9b-9a)
+e^(3x) sin3x (-9a-9b+9b-9a)
Combining like terms:
y"=
e^(3x) cos3x (18b)
+e^(3x) sin3x (-18a)
Let's reorder y like we did y' and y".
y = e^(3x) (acos3x +bsin3x)
y=e^(3x) cos3x (a) + e^(3x) sin3x (b)
Objective is to find a way to combine or combine constant multiples of y, y', and y" so that a and b are not appearing.
Let's start with the highest order derivative and work down
y"=
e^(3x) cos3x (18b)
+e^(3x) sin3x (-18a)
We need to get rid of the 18b and 18a.
This is what we had for y':
y'=e^(3x) cos3x (3a+3b)+e^(3x) sin3x (3b-3a)
Multiplying this by -6 would get rid of the 18b and 18a in y" if we add them.
So we have y"-6y'=
e^(3x) cos3x (-18a)+e^(3x) sin3x (-18b)
Now multiplying
y=e^(3x) cos3x (a) + e^(3x) sin3x (b)
by 18 and then adding that result to the y"-6y' will eliminate the -18a and -18b
y"-6y'+18y=0
Also the characteristic equation is:
r^2-6r+18=0
This can be solved with completing square or quadratic formula.
I will do completing the square:
r^2-6r+18=0
Subtract 9 on both sides:
r^2-6r+9=-9
Factor left side:
(r-3)^2=-9
Take square root of both sides:
r-3=-3i or r-3=3i
Add 3 on both sides for each:
r=3-3i or r=3+3i
This confirms our solution.
Another way to think about the problem:
Any differential equation whose solution winds up in the form y=e^(px) (acos(qx)+bsin(qx)) will be second order and you can go to trying to figure out the quadratic to solve that leads to solution r=p +/- qi
Note: +/- means plus or minus
So we would be looking for a quadratic equation whose solution was r=3 ×/- 3i
Subtracting 3 on both sides gives:
r-3= +/- 3i
Squaring both sides gives:
(r-3)^2=-9
Applying the exponent on the binomial gives:
r^2-6r+9=-9
Adding 9 on both sides gives:
r^2-6r+18=0
Two buses leave towns 576 kilometers apart at the same time and travel toward each other. One bus travels 12
h
slower than the other. If they meet in 3 hours, what is the rate of each bus?
km
Rate of the slower bus:
Rate of the faster bus:
Answer:
Rate of slower bus; 90 km/h
Rate of faster bus; 102 km/b
Step-by-step explanation:
We know that formula do distance is;
Distance = speed/time
We are told that One bus travels 12h slower than the other.
Let speed of slower bus be x.
Thus;
Speed of faster bus = x + 12
Speed of slower bus = x
After 3 hours, distance by faster bus = 3(x + 12)
Speed of slower bus = 3x
Since the towns are 576 km apart, then;
3(x + 12) + 3x = 576
Divide through by 3 to get;
x + 12 + x = 192
2x + 12 = 192
2x = 192 - 12
2x = 180
x = 180/2
x = 90 km/h
Faster bus speed = 90 + 12 = 102 km/h
how do we write a set in set- builder method?
Answer:
(×:x is a natural number up to 10) just an example
What is the volume of the prism? 2inches, 2 1/4 and 4 inches
Hi there!
»»————- ★ ————-««
I believe your answer is:
18in³
»»————- ★ ————-««
Here’s why:
⸻⸻⸻⸻
Assuming that the figure is a rectangular prism:
⸻⸻⸻⸻
[tex]\boxed{\text{Volume of a rectangular prism is:}}\\\\V = l * w * h\\-----------\\V = 2 * 2.25 * 4\\\\\boxed{V = 18}[/tex]
⸻⸻⸻⸻
»»————- ★ ————-««
Hope this helps you. I apologize if it’s incorrect.
Uuannsnnsnndn d. DND. D
Answer:
im so confused
Step-by-step explanation:
Answer:
what is this goat saying
Solve this application problem using a system of equations: A grocery store recently sold a
bag of peanuts for $0.76 and a bag of pistachios for $3.68. At the end of that day, 50 bags of
peanuts and pistachios were sold for a total of $128.52. How many bags of each were sold?
Answer:
19 bags of peanuts and 31 bags of pistachios were sold.
Step-by-step explanation:
This question is solved by a system of equations.
I am going to say that:
x is the number of bags of peanuts sold.
y is the number of bags of pistachios sold.
50 bags of peanuts and pistachios were sold
This means that [tex]x + y = 50[/tex], that is: [tex]x = 50 - y[/tex]
A grocery store recently sold a bag of peanuts for $0.76 and a bag of pistachios for $3.68. Were sold for a total of $128.52.
This means that:
[tex]0.76x + 3.68y = 128.52[/tex]
Since [tex]x = 50 - y[/tex]
[tex]0.76(50 - y) + 3.68y = 128.52[/tex]
[tex]2.92y = 90.5[/tex]
[tex]y = \frac{90.5}{2.92}[/tex]
[tex]y = 31[/tex]
[tex]x = 50 - y = 50 - 31 = 19[/tex]
19 bags of peanuts and 31 bags of pistachios were sold.
Rewrite the following expanded notation in standard form. 600,000 + 80,000 + 1,000 + 400 + 70 + 5
Answer:
this is the answer
681,474
Match each equation to its graph.
1. y= x-2
2. y= -2x
3. x= -2
4. y= -2
The equation of the graph is : x = -2
What is a graph?A graph is a pictorial representation of the locus of a certain point.
How to draw a graph?A graph can be drawn by picking some fixed points from the locus of the point.
Here, the straight line passes through the points are : (-2,1); (-2,2); (-2,-5);(-2,-5).
Hence, the straight line is to be parallel to the x-axis and the equation of the graph is x= -2.
Learn more about graph here :
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What's the equivalent expression.
(2-7. 5)² =?
Answer:
The Answer of the above question is 30.25
Step-by-step explanation:
Hope it helps you.
PLEASE HELP IF NOT I WILL FAIL
Answer:
C. 5
Step-by-step explanation:
To find the degree of the polynomial, all you have to do is find the largest degree. (aka the largest lil number above the x)
In this case, it's 5.
Change these percentages to decimals.
30%
45%
60%
5%
1%
55%
80%
10%
Simplify the given equation.
5x+ 2(x-3) = -2(x - 1)
0 7 x-6=-2 X-2
0 7 x - 6 = -2 x + 2
0 7 X - 3 = -2 x-1
i’m sorry:/
Answer:
7x - 6 = -2x + 2
Step-by-step explanation:
Hi! First we are going to distribute our "2" and "-2" values to the values in parenthesis.
5x + 2x - 6 = -2x + 2
Now, we can combine our like terms, "5x" and "2x".
7x - 6 = -2x + 2
Since our problem's answers are left in this form, not completely combined our answer is 7x - 6 = -2x + 2.
Hope this Helps! :)
Have any questions? Ask below in the comments and I will try my best to answer.
-SGO
please help, it’s urgent !!!
Answer:
1. purple graph
2. orange graph
3. green graph
4. blue graph
What is the percent discount if a 12,500 car is now on special for 10,250?
Answer:
Step-by-step explanation:
the answer is 2250 percent is = 22.5
Answer:
18% discount
Step-by-step explanation:
Percent discount is found by the following formula:
[tex]\frac{original-discount}{original}[/tex]
In this scenario, the original is 12500 and the discount, or special is 10250.
We can plug this into the formula to get
[tex]\frac{12500-10250}{12500}[/tex]
We can simplify the numerator by subtracting, and we get that answer as 2250.
We get the remainder of the answer as 2250 divided by 12500. We divide that, and get the answer as 0.18, which can be rewritten as 18%.
