Answer:
X=22.5
Step-by-step explanation:
Y=kX
20=15k
k=4/3
For X when Y=30
30=4/3×X
Cross multiply
4X=90
X=22.5
2. A small university is trying to monitor its electricity usage. For a random sample of
30 weekend days (Saturdays and Sundays), the student center used an average of 94.26 kilowatt hours (kWh) with standard deviation 43.29. For a random sample of 60 weekdays, (Monday - Friday), the student center used an average of 112.63 kWh with standard deviation 32.07.(Please show work)
a) Test, at the 5% level, if significantly more electricity is used at the student center, on average, on weekdays than weekend days. Remember to check the conditions, identify the hypotheses, define your parameter, find the test statistic, find the p-value, and give a conclusion in context.
b) Construct a 95% confidence interval for the difference in mean electricity use at the student center between weekdays and weekend days. Use two decimal places in your margin of error.
Using the t-distribution, it is found that:
a) Since the test statistic is greater than the critical value for the right-tailed test, it is found that there is enough evidence to conclude that significantly more electricity is used at the student center, on average, on weekdays than weekend days.
b) The 95% confidence interval for the difference in mean electricity use at the student center between weekdays and weekend days is (3.56, 33.18).
Item a:
At the null hypothesis, it is tested if there is no difference, that is, the subtraction is at most 0, hence:
[tex]H_0: \mu_1 - \mu_2 \leq 0[/tex]
At the alternative hypothesis, it is tested if there is difference, that is, the subtraction is positive, hence:
[tex]H_1: \mu_1 - \mu_2 > 0[/tex]
The standard errors are given by:
[tex]s_1 = \frac{32.07}{\sqrt{60}} = 4.14[/tex]
[tex]s_2 = \frac{43.29}{\sqrt{30}} = 7.9[/tex]
The distribution of the difference has mean and standard deviation given by:
[tex]\overline{x} = \mu_1 - \mu_2 = 112.63 - 94.26 = 18.37[/tex]
[tex]s = \sqrt{s_1^2 + s_2^2} = \sqrt{4.14^2 + 7.9^2} = 8.92[/tex]
The standard deviation are given for the samples, hence, the t-distribution is used.
The test statistic is given by:
[tex]t = \frac{\overline{x} - \mu}{s}[/tex]
In which [tex]\mu = 0[/tex] is the value tested at the hypothesis.
Hence:
[tex]t = \frac{\overline{x} - \mu}{s}[/tex]
[tex]t = \frac{18.37 - 0}{8.92}[/tex]
[tex]t = 2.06[/tex]
The critical value for a right-tailed test, as we are testing if the mean is greater than a value, with a significance level of 0.05 and 30 + 60 - 2 = 88 df is [tex]t^{\ast} = 1.66[/tex]
Since the test statistic is greater than the critical value for the right-tailed test, it is found that there is enough evidence to conclude that significantly more electricity is used at the student center, on average, on weekdays than weekend days.
Item b:
The interval is:
[tex]\overline{x} \pm t^{\ast}s[/tex]
Hence:
[tex]\overline{x} - t^{\ast}s = 18.37 - 1.66(8.92) = 3.56[/tex]
[tex]\overline{x} + t^{\ast}s = 18.37 + 1.66(8.92) = 33.18[/tex]
The 95% confidence interval for the difference in mean electricity use at the student center between weekdays and weekend days is (3.56, 33.18).
A similar problem is given at https://brainly.com/question/25812826
What is the value of x?
Answer:
I am not sure the answer is , if its minus ,divade ,multiply or plus but down the answer is correct
Step-by-step explanation:
17x - 75
× = 75÷17
x= 4.4117647059
Find the equation of the normal to the curve in y=mx+b format : p(t) = 3t^2 - 8t + 3 at t = 3
Answer:
[tex]y=10x+24[/tex]
Step-by-step explanation:
Find the derivative of the function
[tex]p'(t)=\frac{d[p(t)]}{dt}=\frac{d}{dt}(3t^2-8t+3)=6t-8[/tex]
Determine the slope of p(t) at t=3:
[tex]p'(3)=6(3)-8=18-8=10[/tex]
Find p(3):
[tex]p(3)=3(3)^2-8(3)+3=3(9)-24+3=27-21=6[/tex]
Determine y-intercept:
[tex]y=mx+b[/tex]
[tex]6=10(3)+b[/tex]
[tex]6=30+b[/tex]
[tex]-24=b[/tex]
Final equation:
[tex]y=10x-24[/tex]
Ms. Green and Mr. White took their science classes to the museum. Ms. Green spent $262 to
buy 28 student tickets and 4 adult tickets for her class. Mr. White spent $191 for 22 student
tickets and 2 adult tickets for his class.
The price of student's ticket will be $7.5 while on the other hand, the price of adult's ticket will be $13.
Based on the information given, the equations to solve the question will be:
28s + 4a = 262 ....... i
22s + 2a = 191 ....... ii
Multiply equation i by 2
Multiply equation ii by 4
56s + 8a = 524
88s + 8a = 764
Subtract the equations above
32s = 240
s = 240/32 = 7.5
Student's tickets = $7.5
Adult's ticket will be:
22s + 2a = 191 .
22(7.5) + 2a = 191
165 + 2a = 191
2a = 191 - 165
2a = 26
a = 26/2 = 13
Learn more about equations on:
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Interest loans are determined by ______
A. whatever the leader wants to charge
B. your credit profile
C. credit bureaus
D. the amount owed at various times
PLEASE hurry! i need help, my grades are failing and i really need correct answers!
Answer:
I think the answer is D please forgive me if I'm wrong
Dr.Goode prescribed 0.2 grams of cold medicine. This medicine comes in tablets that are 0.5 grams or 0.05 grams. Should his patient take 4 of the 0.5 gram tablets or 4 of the 0.05 gram tablets? Why?
90 POINTS PLS HELP
Answer:
4 of the 0.05 gram tablets
Step-by-step explanation:
4 of the 0.5 tablets would be 2 grams
4 of the 0.05 tablets would be 0.2 grams
How many whole groups of 2 can we make with 7?
Answer:
We can make 3 whole groups of 2.
Hope that helps. x
Step-by-step explanation:
2, 4, 6, 8
The closest number near to 7 is 6 so we do 6 divided by 2 which equals 3.
Will mark brainliest (2 possible answers. NO LINKS OR ANSWERS WITHOUT EXPLANATION)
A box and whisker plot is made up of 5 pieces of information: the minimum, 1st/lower quartile, median, 3rd/upper quartile, and maximum.
Start by placing a dot on the minimum and maximum values. These are the "whiskers" of the box plot.
Next, we'll graph the lower and upper quartiles. On these values, draw vertical lines. We are given the lower quartile, but will need to find the upper quartile.
IQR = upper quartile - lower quartile
225 = x - 120
x = 345 minutes = 5 hours, 45 minutes
Now that we know the upper quartile, you will also draw a line on that value. Feel free to connect the lines to make the "box".
Lastly, we'll graph the median. This is another vertical line on the value. It should be directly in the middle of the lower and upper quartiles. It will be inside the box.
Hope this helps and if you have any further questions, please let me know! :)
5x – 2y = 30
Complete the missing value in the solution to the equation. (8, ?)
Answer:
5
Step-by-step explanation:
Hope this helps
Answer:
(8,5)
Step-by-step explanation:
x=8
5*8-2y=30
40-2y=30 . subtract 40 from both sides
-2y=-10 . divide both sides by-2
y=5
what equation can help you find out how many adults are there if tickets cost $9 for adults plus one child and $3 for children the total cost of the movie is $48
Answer:
48 ÷12 will help you 48 is cost divided by total cost which means cost of one adult and one child
(4x2 - x - 7) + (2x3 + 6x2 - 11)
Adding polynomials
Answer:
2x3 + 10x2 - x - 18
Step-by-step explanation:
hope this helps! goodluck & enjoy the rest of ur day /or night.
Answer:
(4x2 - x - 7) + (2x3 + 6x2 - 11) Adding polynomials
Step-by-step explanation:
Which statement about the slope of the line is true?
It is −2 throughout the line.
It is fraction negative 1 over 2 throughout the line.
The slope from point O to point A is one-half times the slope of the line from point A to point B.
The slope from point O to point A is two times the slope of the line from point A to point B.
Explanation:
Let's say we started at point B (-6, 3). To get to point A(-4,2), we move down 1 and to the right 2. This movement determines the slope.
slope = rise/run = -1/2
rise = -1 and run = 2
A negative rise value means we go downhill when moving to the right.
Help
Activity:
2x²2+2x-312=0
Answer:
Step-by-step explanation:
As Trish and tan were traveling to the state cross country meet, they followed their progress along on a map. The map showed a scale of 1 inch equaling 60 miles. Their route’s total length on the map is 2 1/2 inches long. How far will they be traveling to the meet? Show your work.
The cost was 1,784. they also had to pay 7.25% sales tax. what was the total amount paid
Answer:
1913.34
Step-by-step explanation:
We multiply 1,784 by 0.00725. OR if you have a calculator that multiplies percentages you can write it out as 1784 * 7.25%.
write the equation of the line in fully simplified slope-intercept form
Answer:
y=1/2x+8
Step-by-step explanation:
grab 2 points in this case (4,10) and (0,8)
use rise over run formula so it rises 2 and goes over 4
so 2/4 then simplify and you get 1/2
and the y intercept is 8 because thats when the slope touches the y line
so using the equation y=mx+b when m is slope and b is y interecpt
the answer should be y=1/2x+8
Answer:
y=2x+8
Step-by-step explanation:
8=b m=y_ý/x_x`=2
y=ax+b
y=2x+8
Where is point E located?
(2,0)
(2,2)
(0,2)
(0,0)
Answer:
Send me a picture of the graph and I gottchu =)
Step-by-step explanation:
Answer:
I need a picture of the graph to answer that
how do I find the volume of this shape?
Answer:
length times witdth times height
(THE ULTIMATE QUESTION)solve one step equation (will also give Brainliest)
1. 3x = -18
2.x/4 = 16
3.-9x = 45
4.x + 8 = -10
5.-3x = -9
6.x/-2 = -3
Answer:
1 = --6
2 x=64
3 x= --5
4 x= --18
5 x=3
6 x=6
Step-by-step explanation:
GIMME BRANlIEST PLZZZ
Please help, due date is tomorrow
Answer:
1/4 is on the second line
3/8 is the the third one
3/8 is bigger
Hope This Helps!!!
Answer:
Hope this helps you.......
Given that x=2, y=5 and z=3 evaluate the value of x-2y
Answer:So firstly, plug in the numbers into the expression:
Next, solve the exponents:
Next, solve the multiplications:
Lastly, combine everything, and your answer will be -23.
Step-by-step explanation:
Answer:
-23
Step-by-step explanation:
By substituting the given numeric values for x,y and z into the expression.
That is
(3)3−2(5)2−3(3)3+(−3)4
------------------------------------------------
I'll evaluate each term separately.
(3)3=3×3×3=9×3=27
2(5)2=2×(5×5)=2×25=50
3(3)3=3×(3×3×3)=3×27=81
(−3)4=[(−3)×(−3)]×[(−3)×(−3)]=9×9=81
-------------------------------------------------
Replace these values back into the expression , noting the values which are subtracted.
⇒27−50−81+81=27−50=−23
I really need help it’s due soon!!! I will be asking more questions soon
Step-by-step explanation:
Yards of red material = 1.75
Yards of blue material = 1.75 x 1.2 = 2.1 yards
So the blue material is 2.1 yards
Which points on the curve of x^2 - xy - y^2 = 5 have vertical tangent lines?
We need to differentiate this with respect to x to see if we can find an expression for the derivative of y at various points. That will be the slope of the tangent to the curve. Then we want to see where that derivative might be infinite -- i.e., where the tangent is vertical.
It's not written as a function, but it can still be differentiated using the chain rule:
x2 + xy + y2 = 3
(2x) + (x dy/dx + y dx/dx) + (2y dy/dx) = 0
(I used parentheses to show the differentiation of each term in the original equation.)
2x + x dy/dx + y + 2y dy/dx = 0
2x + y = -x dy/dx - 2y dy/dx
2x + y = dy/dx (-x -2y)
-(2x + y)/(x + 2y) = dy/dx
We have the derivative of y, but it's defined partly in terms of y itself. That's OK. Let's go on...
So where would the slope be infinite? That would happen when x + 2y = 0, or y = -x/2
Let's plug that in for y in the original equation to find points where that's the case.
x2 + xy + y2 = 3
x2 + x(-x/2) + (-x/2)2 = 3
x2 - x2/2 + x2/4 = 3
3x2 / 4 = 3
x2 = 4
x = ±2
So we have two x values where the tangent might be vertical. Let's plug them into the equation and see what the y values are. First x = 2...
x2 + xy + y2 = 3
4 + 2y + y2 = 3
y2 + 2y + 1 = 0
(y + 1)2 = 0
y = -1
So at the point (2, -1) the tangent is vertical.
Now try x = -2...
x2 + xy + y2 = 3
4 - 2y + y2 = 3
y2 - 2y + 1 =0
(y - 1)2 = 0
y = 1
So at the point (-2, 1) the tangent is vertical.
solve using substitution
x-10y=10
x= -10
Answer:
y = -2Step-by-step explanation:
x - 10y = 10=> -10 - 10y = 10=> -10y = 10 + 10=> -10y = 20=> y = -2Conclusion:
Therefore, y = -2.
Hoped this helped.
[tex]GeniusUser[/tex]
need help dont want to fail
Answer:
I think the correct answer is D since the arrows go infinite ways. Let me know if im right. :)
Step-by-step explanation:
Which graph shows the original figure rotated 180 degrees
Answer:
I believe it would be B.
Step-by-step explanation:
Half a circle is 180 degrees, which is the location of option B. In other words you just rotate it halfway around and you'll find it at 180°.
how many 4/5 are in 2
Answer:
1/10
Step-by-step explanation:
please help me!
ty :)
Answer:
5
Step-by-step explanation:
The distance between the points in RISE/RUN is 10/2.
10/2 = 5. Your slope is 5
Hope that helps. Brainliest is appreciated
Please answer hurrryy
Answer:
the answer is 270714.285714 or just 270714.2 careful \
Step-by-step explanation:
Find equivalent expressions of 3+2x−9−4x+11+5x−x. Choose three expressions.
The expression that is equivalent to the expression, 3 + 2x − 9 − 4x + 11 + 5x − x, is: 2x + 5.
What are Equivalent Expressions?Expressions that have the same value are said to be equivalent expressions.
Evaluate 3+2x−9−4x+11+5x−x:
3 + 2x − 9 − 4x + 11 + 5x − x
Add like terms together
2x - 4x + 5x - x + 3 - 9 + 11
2x + 5
Learn more about equivalent equations on:
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#SPJ2
Answer:
Step-by-step explanation:
The expression that is equivalent to the expression, 3 + 2x − 9 − 4x + 11 + 5x − x, is: 2x + 5.
