The average natural gas bill for a random sample of 21 homes in the 19808 zip code during the month of February was $311.90 with a sample standard deviation of $51.60. Based on the sample, construct a 90% confidence interval for the true mean natural gas bill for homes in the 19808 zip code area in February.
Answer:
The 90% confidence interval for the true mean natural gas bill for homes in the 19808 zip code area in February is between $292.48 and $331.32
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
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 = 21 - 1 = 20
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 20 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 1.7247
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 1.7247\frac{51.60}{\sqrt{21}} = 19.42[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 311.9 - 19.42 = $292.48
The upper end of the interval is the sample mean added to M. So it is 311.9 + 19.42 = $331.32
The 90% confidence interval for the true mean natural gas bill for homes in the 19808 zip code area in February is between $292.48 and $331.32
a storm blew down many trees. several neighbors rented a chain saw for $232.85 and helped each other cut up and stack wood. the rental company charges $73.95 per day plus a $11 sharpening fee. how many days was the saw rented?
9514 1404 393
Answer:
3 days
Step-by-step explanation:
You can estimate the answer (correctly) by observing that 3 × 70 is 210. This is close enough to 232.85 that you know the number of rental days is not 2 or 4.
The equation for the number of days (d) is ...
73.95d +11 = 232.85 . . . $73.95 per day plus an extra fee
73.95d = 221.85 . . . . . . subtract 11
d = 221.85/73.95 = 3 . . . . divide by the coefficient of d
The saw was rented for 3 days.
Answer:
3 days
Step-by-step explanation:
What is the value of the expression below? 7/10÷3/8
A.21/80
B.1 13/15
C.3 17/21
D.15/28
3(v +67)=-13 I need help
Answer:
v= -71.3 there you go hope this helps
The manager of a restaurant recorded how many people were in different groups of
customers and how much those groups spent on food and beverages. The scatterplot below
shows the data she recorded.
Answer:
$135
Step-by-step explanation:
Answer:
D
Step-by-step explanation:
hows it goin my boi
Martin is making a candy that contains 90% milk chocolate and the rest caramels. The candy has 3 pounds of caramels.
Part A: Write an equation using one variable that can be used to find the total number of pounds of milk chocolate and caramels in the candy. Define the variable used in the equation. (5 points)
Part B: How many pounds of milk chocolate are present in the candy? Show your work.
Let x be the weight of the candy in pounds, then 0.9x is the weight of the milk chocolate in pounds
The weight of the caramels in the candy is 3 pounds, so
An equation that can be used find the total number of pounds of milk chocolate and caramels in the candy is
0.9x + 3 = x ⇒ x = 30
So there are 0.9(30) = 27 pounds of milk chocolate in the candy.
hope this helps
Question 4 Incorrect answer. Incorrect. Try again. Two suppliers manufacture a plastic gear used in a laser printer. The impact strength of these gears measured in foot-pounds is an important characteristic. A random sample of 10 gears from supplier 1 results in x Overscript bar EndScripts Subscript 1 Baseline equals 289.30 and and another random sample of 16 gears from the second supplier results in x Overscript bar EndScripts Subscript 2 Baseline equals 321.50 and Is there sufficient evidence to conclude that the variance of impact strength is different for the two suppliers
Answer:
Since the calculated t = -3.9886 falls in the critical region t ∝/2 ≥±2.101 we reject the null hypothesis and conclude that variance of impact strength is different for the two suppliers
Step-by-step explanation:
The given data is
Sample1 mean = x1` = 289.3
Sample 1 size = n1= 10
Sample 1 std. dev= s1= 22.5
Sample2 mean = x2` = 321.5
Sample 2 size = n2= 16
Sample 2 std. dev= s2= 21
1)Formulate the null and alternate hypothesis as
H0: σ₁=σ₂ against the claim Ha: σ₁ ≠σ₂
2)The test statistic is
t= (x1`- x2`) / √ s1²/n1+ s2²/n2
where degrees of freedom = d.f=
υ = [s₁²/n1 + s₂²/n2]²/ (s₁²/n1 )²/ n1-1 + (s₂²/n2)²/n2-1
3) the significance level chosen is ∝= 0.05
4) Calculating the d.f
υ = [s₁²/n1 + s₂²/n2]²/ (s₁²/n1 )²/ n1-1 + (s₂²/n2)²/n2-1
= [21²/10 + 22.5²/16] / [(21/²10)² /9 + (22.5²/16)²/15]
= 18
5) the critical region for ∝= 0.05 for 18 d.f = ±2.101 for two sided test
6) t= (x1`- x2`) / √ s1²/n1+ s2²/n2
t= 289.3- 321.5/√21²/10 + 22.5²/16
t= -32.2/√44.1+31.64
t= -32.2/8.0729
t= -3.9886
7) Conclusion
Since the calculated t = -3.9886 falls in the critical region t ∝/2 ≥±2.101 we reject the null hypothesis and conclude that variance of impact strength is different for the two suppliers
Which ordered pair is on the x axis?
Answer:
0,0
Step-by-step explanation:
Given the definitions of f(x) and g(x) below, find the value of (g o f) (-3)
f(x)=2x^2+6x+9
g(x)=3x-6
Answer:
21
Step-by-step explanation:
(g o f) (-3) = g ( f(-3) )
First, let's find f(-3):
f(x)=2x²+6x+9
f(-3)=2(-3²)+6(-3)+9
f(-3)=18-18+9
f(-3)=9
Now that we know the value of f(-3), we can sub this into g(f(-3)):
g ( f(-3) ) = g(9)
Find g(9):
g(9)=3x-6
g(9)=3(9)-6
g(9)=27-6
g(9)=21
Mark, Anthony, and Derek, are going on a road trip and will take turns driving the car. They need to decide who will drive first.
Which method assures that each of the three friends has a fair chance of being selected to drive first?
O A. "Using a random number generator, generate an integer. If the number is negative, Mark drives first. If the number is positive,
Anthony drives first. If the number is 0, Derek drives first.
OB.
Flip two fair coins. If both coins land on tails, Mark drives first. If both coins land on heads, Anthony drives first. If one coin
lands on tails and the other lands on heads, Derek drives first.
O C. Spin a spinner with four equal-sized sections labeled A, B, C, and D. If the spinner lands on A, Mark drives first. If the spinner
lands on B, Anthony drives first. If the spinner lands on C, Derek drives first. If the spinner lands on D, Mark drives first.
OD. Roll an ordinary die. If the die lands on 1 or 4, Mark drives first. If the die lands on 2 or 5, Anthony drives first. If the die lands
on 3 or 6, Derek drives first.
Answer: Option D
Step-by-step explanation:
I got it right on Edmentum/Plato
Dilations-He Said, She Said (12/10)
Answer:
um.....
Step-by-step explanation:
Cory writes the polynomial x7 + 3x5 + 3x + 1. Melissa writes the polynomial x7 + 5x + 10. Is there a difference between the degree of the sum and the degree of the difference of the polynomials?
Answer:
Yes??
Step-by-step explanation:
7+3x5+3x+1
7+15+3x+1
22+3x+1
3x+23
7+5x+10
5x+17
Yes, much difference
---
hope it helps
sorry if i'm wrong, sum of the x's confused me
Answer:D
Step-by-step explanation:
30 POINT FOR BRAINLIEST ANSWER!!!!!
Answer:
[tex]H)39.6[/tex]
Step-by-step explanation:
To get the mean, you have to add all the numbers, then divide the sum by the amount of individual numbers there are.
In this problem, we see that there are 5 different numbers. If we add all those numbers together, they will equal 198.
[tex]198[/tex] ÷ [tex]5 = 39.6[/tex]
What is total area of the shaded sections
Answer:
Step-by-step explanation:
The shaded region is triangle.
Base = 1.1 in
Height = 3.8 in
Area of triangle = [tex]\frac{1}{2}*base * height[/tex]
[tex]=\frac{1}{2}*1.1*3.8\\\\= 1.1 * 1.9\\\\= 2.09 in^{2}[/tex]
Area of shaded region = 2 * 2.09 = 4.18 square inches
Give the most precise
name for the quadrilateral.
Then, find x and y.
A) square x=80 y=5
B) rhombus x=80 y=5
C) rhombus x=100 y=10
D) square x=80 y=10
E) rectangle x=100 y=7
Answer:
B
Step-by-step explanation:
quadrilaterals= 360 degrees, now if you sub 80 for x, 80 +100 is 180 x 2( counting the other side) so 180 x 2 is 360
*I know there is a better way to explain it, but this is a way i find it
can someone please answer this im so tired man
Answer:
5. 1 1/2 ( c )
6. 3 7/10 ( c )
Step-by-step explanation:
i can help u with the whole test if u give me brainliest
Valentina buys a chandelier priced at $713. If the sales tax is 4%, how
much tax will
Valentina pay?
Answer:
$741.52 TRUSTTT
Step-by-step explanation:
Answer:
x + (tax percent out of 100)*x, which is 748.65.
Two sides of a right triangle have lengths of 78 inches and 30 inches. The third side is not the hypotenuse. How long is the third side ?
Answer:
the answer is 72 inches
Step-by-step explanation:
a²+b²=c²
a²+900=6084
a²=5184
a=72
Solve the quadratic equation x2 – 10x + 14 = –4 by completing the square.
Question 3 options:
A)
x = 5 ±
B)
x = –5 ±
C)
x = –7 ±
D)
x = 7 ±
Answer:
[tex] x = 5 \pm \sqrt{7} [/tex]
Step-by-step explanation:
x^2 - 10x + 14 = -4
Subtract 14 from both sides.
x^2 - 10x = -18
To complete the square, add the square of half of the x-term's coefficient.
x-term coefficient: -10
half of it: -5
squared: (-5)^2 = 25
Add 25 to both sides.
x^2 - 10x + 25 = -18 + 25
(x - 5)^2 = 7
Take square root of both sides. Be careful to include ± on the right side.
[tex] x - 5 = \pm \sqrt{7} [/tex]
Add 5 to both sides.
[tex] x = 5 \pm \sqrt{7} [/tex]
Need the answer to x and y !
x = 2 y = 7
Step-by-step explanation:
the explan at the pic
Question 4
1p
Given the chart below, calculate the number of days one
could expect to have off due to hurricanes. Round to the nearest
day (enter your answer as a number only, you don't need to write "days" at the
end)
Number of Hurricane Days Each School Year
1
2
3
4
0
5
6
7
Days:
Chances of
having that
many days oft:
03
02
0.25
0.2
0.02
0.01
0.01
0.01
Answer:
2
Step-by-step explanation:
Given
See attachment for chart
Required
Number of off days
To do this, we simply calculate the expected value of the chart.
This is calculated as:
[tex]E(x) = \sum x * f[/tex]
Where
x = days
f = chances
So, we have:
[tex]E(x) = 0* 0.3 + 1 *0.2 + 2 * 0.25 + 3 * 0.2 + 4 * 0.02 + 5 * 0.01 + 6 * 0.01 + 7 * 0.01[/tex]
[tex]E(x) = 1.56[/tex]
[tex]E(x) \approx 2[/tex]
Select all statements that are true.
An acute triangle can be equilateral
An obtuse triangle can have more than one obtuse angle.
An equilateral triangle is always equiangular.
A right triangle can be scalene.
An acute triangle can be sosceles
A scalene triangle can be equilateral
The true statements are as follows
An acute triangle can be equilateral .An equilateral triangle is always equiangular. A right triangle can be scalene. An acute triangle can be isosceles.The following statements considered to be false:
An obtuse triangle can have more than one obtuse angle.A scalene triangle can be equilateral.Therefore, the above statements are considered true.
Learn more: brainly.com/question/17429689
I need to know the surface area of these
9514 1404 393
Answer:
245 cm²
Step-by-step explanation:
The surface area of a cone is given by ...
SA = πr(r +s) . . . . where r is the radius, and s is the slant height
Filling in the given values, we have ...
SA = (3.14)(3 cm)(3 cm +23 cm) = (3.14)(3)(26) cm² ≈ 245 cm²
The surface area of the cone is about 245 cm².
If I have 2 apples and take away 1 apple, how many peanuts do I have left?
Answer:
Cannot be determined with the information given in and of itself.
Step-by-step explanation:
You would have 1 apple left. However, there is absolutely no information given about the original amount of peanuts, how many peanuts are given to you, how many peanuts are taken from you, how many apples to a peanut, etc. etc. No answer in peanuts can be given.
I would appreciate Brainliest, but no worries.
Answer:
0
Step-by-step explanation:
if you have 2 and you take one away you have 1,
you'll have 0 peanuts since apples can't become peanuts, unless you have them already or buy them; apples won't help you get peanuts.
pls answer fast this is my last assignments is giving 30 points and make the brainiest
Answer:
obama your mama she looks like joe mama
Jessica is making a cake. The recipe calls for 2 3/4 cups of flour. She only has a measuring cup that holds 1/4 cup. Explain how she can use the measuring cup that holds 1/4 cup to measure 2 3/4 cups of flour.
Answer: Jessica can use her measuring cup 11 times.
(hope this helps!)
explain how the diagram can help find the area of a circle
Answer:
Step-by-step explanation:
This is a really famous diagram! The circle has been divided into many wedges (think slices of pizza!). The wedges have been colored alternately blue and yellow, then the wedges were rearranged to form a "rectangle" -- well, it's approximately a rectangle because the wedges have arcs (pieces of a circle) on them. See how the bottom and top edges of the rectangle look bumpy?
The area of the "rectangle" is approximately [tex]\pi r^2[/tex] . The reason is that the height of the rectangle is r , the radius of the circle. And the length of the rectangle is about [tex]\pi r[/tex] -- half the circumference of the circle. It's half because the circumference is in the bumpy parts of the wedges--half blue, half yellow.
The approximation improves as the number of wedges increases. In fact, as the number of slices (sorry, pizza again) gets larger, the length of the rectangle gets closer and closer to half the circumference. In other words, making more wedges makes the rectangle less bumpy!
Help please question in the picture
Answer:
17.5
Step-by-step explanation:
The area of a triangle is (height*base)divided by two
(the eight is really unnecessary)
so 7=base
8=height
7*5=35
35/2=17.5
Select all numbers that have and absolute value of 0.6
Is 7/2 the same as 1/5
Answer:
No.
Step-by-step explanation:
Calculation: 2/4 + 3/4 - fraction calculator. Result: 5/4 = 1 1/4.