Answer:
x =(7-√217)/2=-3.865
x =(7+√217)/2=10.865 mark brainliest please
Step-by-step explanation:
Factoring x2-7x-42
The first term is, x2 its coefficient is 1 .
The middle term is, -7x its coefficient is -7 .
The last term, "the constant", is -42
Step-1 : Multiply the coefficient of the first term by the constant 1 • -42 = -42
Step-2 : Find two factors of -42 whose sum equals the coefficient of the middle term, which is -7 .
-42 + 1 = -41
-21 + 2 = -19
-14 + 3 = -11
-7 + 6 = -1
-6 + 7 = 1
-3 + 14 = 11
-2 + 21 = 19
-1 + 42 = 41
Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored
Equation at the end of step 1 :
x2 - 7x - 42 = 0
Step 2 :
Parabola, Finding the Vertex :
2.1 Find the Vertex of y = x2-7x-42
Parabolas have a highest or a lowest point called the Vertex . Our parabola opens up and accordingly has a lowest point (AKA absolute minimum) . We know this even before plotting "y" because the coefficient of the first term, 1 , is positive (greater than zero).
Each parabola has a vertical line of symmetry that passes through its vertex. Because of this symmetry, the line of symmetry would, for example, pass through the midpoint of the two x -intercepts (roots or solutions) of the parabola. That is, if the parabola has indeed two real solutions.
Parabolas can model many real life situations, such as the height above ground, of an object thrown upward, after some period of time. The vertex of the parabola can provide us with information, such as the maximum height that object, thrown upwards, can reach. For this reason we want to be able to find the coordinates of the vertex.
For any parabola,Ax2+Bx+C,the x -coordinate of the vertex is given by -B/(2A) . In our case the x coordinate is 3.5000
Plugging into the parabola formula 3.5000 for x we can calculate the y -coordinate :
y = 1.0 * 3.50 * 3.50 - 7.0 * 3.50 - 42.0
or y = -54.250
Parabola, Graphing Vertex and X-Intercepts :
Root plot for : y = x2-7x-42
Axis of Symmetry (dashed) {x}={ 3.50}
Vertex at {x,y} = { 3.50,-54.25}
x -Intercepts (Roots) :
Root 1 at {x,y} = {-3.87, 0.00}
Root 2 at {x,y} = {10.87, 0.00}
Solve Quadratic Equation by Completing The Square
2.2 Solving x2-7x-42 = 0 by Completing The Square .
Add 42 to both side of the equation :
x2-7x = 42
Now the clever bit: Take the coefficient of x , which is 7 , divide by two, giving 7/2 , and finally square it giving 49/4
Add 49/4 to both sides of the equation :
On the right hand side we have :
42 + 49/4 or, (42/1)+(49/4)
The common denominator of the two fractions is 4 Adding (168/4)+(49/4) gives 217/4
So adding to both sides we finally get :
x2-7x+(49/4) = 217/4
Adding 49/4 has completed the left hand side into a perfect square :
x2-7x+(49/4) =
(x-(7/2)) • (x-(7/2)) =
(x-(7/2))2
Things which are equal to the same thing are also equal to one another. Since
x2-7x+(49/4) = 217/4 and
x2-7x+(49/4) = (x-(7/2))2
then, according to the law of transitivity,
(x-(7/2))2 = 217/4
We'll refer to this Equation as Eq. #2.2.1
The Square Root Principle says that When two things are equal, their square roots are equal.
Note that the square root of
(x-(7/2))2 is
(x-(7/2))2/2 =
(x-(7/2))1 =
x-(7/2)
Now, applying the Square Root Principle to Eq. #2.2.1 we get:
x-(7/2) = √ 217/4
Add 7/2 to both sides to obtain:
x = 7/2 + √ 217/4
Since a square root has two values, one positive and the other negative
x2 - 7x - 42 = 0
has two solutions:
x = 7/2 + √ 217/4
or
x = 7/2 - √ 217/4
Note that √ 217/4 can be written as
√ 217 / √ 4 which is √ 217 / 2
Solve Quadratic Equation using the Quadratic Formula
2.3 Solving x2-7x-42 = 0 by the Quadratic Formula .
According to the Quadratic Formula, x , the solution for Ax2+Bx+C = 0 , where A, B and C are numbers, often called coefficients, is given by :
- B ± √ B2-4AC
x = ————————
2A
In our case, A = 1
B = -7
C = -42
Accordingly, B2 - 4AC =
49 - (-168) =
217
Applying the quadratic formula :
7 ± √ 217
x = —————
2
√ 217 , rounded to 4 decimal digits, is 14.7309
So now we are looking at:
x = ( 7 ± 14.731 ) / 2
Two real solutions:
x =(7+√217)/2=10.865
or:
x =(7-√217)/2=-3.865
Answer:
x^2 - 7x - 42
x^2 - x (21 - 14 ) - 42
x^2 - 21x + 14x -42
7x ( x - 3) + 14 ( x- 3)
(x -3) (7x + 14)
hope this helps you
Calculate 12 x 15 by changing the numbers into friendlier numbers as we saw in the videos. Show how you work it out – write out your methods using the number keys on your computer here: Please write your response.
Answer:
The product 12 × 15 in friendlier numbers is (10 + 2) × (10 + 5) = 180
Step-by-step explanation:
The parameter given are;
To 12 × 15 by changing the numbers into friendlier numbers
The product in 12 × 15 written with friendlier numbers (or in a simplified format can be given as follows;
12 × 15 = (10 + 2) × (10 + 5)
Which gives;
(10 + 2) × (10 + 5) = 10² + 10 × 5 + 2 × 10 + 2 × 5
From which we have;
10² + 10 × 5 + 2 × 10 + 2 × 5 = 100 + 50 + 20 + 10 = 180
Therefore;
12 × 15 = 180.
a cruse ship can cover 17 nautical miles in 340 minutes how many nautical miles will it travel in 300 minutes
Answer:
1 minute to sail 17/306 = 1/18th of a nautical mile
234 minutes to sail 1/18 x 234 = 13 nautical miles.
Hope this helps :-)
Step-by-step explanation:
Answer:
15 nautical miles
Step-by-step explanation:
Set up a proportion: 340/17=300/x simplify the first one 20/1=300/x 20x=300 x=15 so 15 nautical miles
Please mark brainliest if correct Hope this helps :D
NEED HELP ASAP!!!! // 20 points
The expression 7n could be translated as _____.
seven times a number
seven more than a number
a number increased by seven
the quotient of seven and a number
Each of the following correctly match an English phrase with a mathematical expression except _____.
a number is tripled, m + 3
the quotient of a number and three, m/3
three less than a number, m – 3
three increased by a number, 3 + m
Nathan is twice as old as his sister. If Nathan’s age is represented by n, which of the following would represent his sister’s age?
n + 2
n – 2
2 n
n/2
Answer:
1) 7 times a number
2) m + 3
3) n/2
Step-by-step explanation:
places.) (a) Compute a 95% CI for μ when n=25 and x
ˉ
=53.6. (, ) watts (b) Compute a 95% CI for μ when n=100 and x
ˉ
=53.6 ( , ) watts (c) Compute a 99%CI for μ when n=100 and x
ˉ
=53.6. ( , ) watts (d) Compute an 82% CI for μ when n=100 and x
ˉ
=53.6. ( , ) watts (e) How large must n be if the width of the 99% interval for μ is to be 1.0 ? (Round your answer up to the nearest whole number.) n=
(a) 95% CI for μ when n=25 and x will be (51.68, 55.52) watts .
We use the formula for a confidence interval for the mean with known standard deviation:
CI = (x - z*σ/√n, x+ z*σ/√n)
where x is the sample mean, σ is the population standard deviation, n is the sample size, and z is the z-score corresponding to the desired confidence level (95% in this case).
Since the standard deviation is unknown, we use the sample standard deviation s as an estimate for σ.
Plugging in the values, we have:
CI = (53.6 - 1.96*(s/√25), 53.6 + 1.96*(s/√25))
= (51.68, 55.52) watts
(b) 95% CI for μ when n=100 and x will be (52.42, 54.78) watts.
Using the same formula as in part (a), we have:
CI = (53.6 - 1.96*(s/√100), 53.6 + 1.96*(s/√100))
= (52.42, 54.78) watts
(c) 99%CI for μ when n=100 and x will be (51.96, 55.24) watts
Using the same formula as in part (a) with a z-score of 2.58 (corresponding to a 99% confidence level), we have:
CI = (53.6 - 2.58*(s/√100), 53.6 + 2.58*(s/√100))
= (51.96, 55.24) watts
(d) 82% CI for μ when n=100 and x will be (52.95, 54.25) watts
Using the same formula as in part (a) with a z-score of 1.305 (found using a standard normal table or calculator), we have:
CI = (53.6 - 1.305*(s/√100), 53.6 + 1.305*(s/√100))
= (52.95, 54.25) watts
(e) The value of n will be 267.
We use the formula for the width of a confidence interval:
width = 2*z*(s/√n)
where z is the z-score corresponding to the desired confidence level (99% in this case) and s is the sample standard deviation.
Solving for n, we have:
n = (2*z*s/width)^2
Plugging in the values, we get:
n = (2*2.58*s/1.0)^2
= 266.49
Rounding up to the nearest whole number, we get n = 267.
To know more about statistics refer here:
https://brainly.com/question/31538429?#
#SPJ11
Triangle MNP is congruent to triangle SQR. If measure S = (3x+5), measure N = (4x-6), measure R = (2x+1), and measure Q = (94-x), find the value of x.
For the given question value of x will be 20
Congruent triangle:
If two triangle are congruent then all the corresponding sides and corresponding angles ill be equal. Symbol for congruent is ≅.Congruent triangles are also known as identical triangle.
For example,
if ΔMNP and ΔSQR are congruent,
that is,
if ΔMNP ≅ ΔSQR
then,
∠M = ∠S
∠N = ∠Q
∠P = ∠R
and ,
MN = SQ , NP = QR , MP = SR
According to question,
∠S = (3x+5)°
∠N = (4x-6)°
∠R = (2x+1)°
∠Q = (94-x)°
As,
ΔMNP ≅ ΔSQR
so,
∠N = ∠Q
(4x-6)° = (94-x)°
4x + x = 94 + 6
5x = 100
x = 100/5
x = 20
Hence, for the given congruent triangle ΔMNP and ΔSQR value of x will be 20.
To learn more about Congruent triangle visit: https://brainly.com/question/22062407
#SPJ1
brian pays £275.23 a year on his car insurance
the insurance company raises the price by 2.6%
how much does the insurance cost now ?
give your answer to 2 DP
What is the difference between minimum and infimum?
The terms minimum and infimum are both related to the concept of lower bounds in mathematics. A minimum is the smallest value in a set of numbers, whereas an infimum is the greatest lower bound of a set.
A minimum is a value that is less than or equal to all other values in the set, while an infimum is a value that is less than or equal to all other values in the set, but not necessarily the smallest value.
For example, if we consider the set {2, 4, 6}, the minimum is 2 and the infimum is also 2. However, if we consider the set {2, 4, 6, 8}, the minimum is 2 and the infimum is 4. In the latter set, 4 is the greatest lower bound, meaning that all other values in the set are greater than or equal to 4.
know more about mathematics here
https://brainly.com/question/15209879#
#SPJ11
HELP QUICK PLS WILL GIVE BRAINLIEST
The total cost after tax to repair Deborah’s computer is represented by 0.08 (50h) + 50h, where h represents the number of hours it takes to repair Deborah’s computer. What part of the expression represents the amount of tax Deborah has to pay? Explain.
Answer:
0.08(50h)
Step-by-step explanation:
0.08(50h)+50h=
8/100(50h)+50h=
0.08(50h)+50h
It's 0.08 of 50h, so
0.08(50h)
keep a smile :) Peanuts cost $1.50 per pound. How much does 2 pounds of peanuts cost?
Answer:
3 dollars
Step-by-step explanation:
Answer:
$3
Step-by-step explanation:
If the unit price is 1.5 , you multiply it by 2 to get the price of 2 pounds
1.5*2=$3
A textbook is opened at random. What page numbers is the book opened to if the product of the opened page numbers is 132?
The book is opened to pages 11 and 12.
How to get the product of the page
So, we can write the equation:x * (x + 1) = 132
Expanding the equation, we get:
x² + x = 132
To solve for x, we need to rewrite the equation as a quadratic equation:
x²+ x - 132 = 0
Now, we can factor the quadratic equation:
(x - 11)(x + 12) = 0
This equation has two solutions for x:
x = 11
x = -12
Since page numbers cannot be negative, we discard the second solution. Thus, the left-hand page number is 11, and the right-hand page number is 11 + 1 = 12.
So, the book is opened to pages 11 and 12.
Read more on product of numbers here : https://brainly.com/question/25301924
#SPJ1
Which of the following is the correct null hypothesis for an independent-measures t test?
a. M1 - M2 = 0
b. M1 - M2 ǂ 0
c. µ1 - µ2 = 0
d. µ1 - µ2 ǂ 0
Option a,The correct null hypothesis for an independent-measures t test is option a, which states M1 - M2 = 0.
An independent-measures t test is a statistical test used to compare the means of two independent groups. In this test, the null hypothesis represents the assumption that there is no significant difference between the means of the two groups. The null hypothesis is usually expressed in terms of the difference between the means of the two groups, denoted by M1 and M2.
In summary, the correct null hypothesis for an independent-measures t test is option a, which states M1 - M2 = 0. This null hypothesis assumes that there is no significant difference between the means of the two groups and any observed difference is due to chance. Option b assumes a significant difference between the means, while options c and d use population means instead of sample means. It is important to correctly specify the null hypothesis in a statistical test to ensure that the conclusions drawn from the analysis are valid.
To know more about null hypothesis visit :-
https://brainly.com/question/19263925
#SPJ11
Consider 8.08 x 5.07.How many digits after the decimal point will the product have?Number of digits =
we have
8.08x5.07=40.9656
therefore
the product has 4 digits after the decimal point
Solve the problem.
A pollster wishes to estimate the true proportion of U. S. Voters that oppose capital punishment. How many voters should be surveyed in order to be 96 percent confident that the true proportion is estimated to within 0. 02?
A)2627
B)53
C)2626
D)1
The pollster should survey 2627 voters in order to be 96 percent confident that the true proportion of U.S. voters opposing capital punishment is estimated to within 0.02.
To determine the sample size needed for estimating a proportion, we can use the formula:
n = (Z^2 * p * q) / E^2
where:
n is the sample size
Z is the z-value corresponding to the desired confidence level (96 percent confidence corresponds to a z-value of approximately 1.75)
p is the estimated proportion (since we don't have an initial estimate, we can assume a conservative estimate of 0.5)
q is 1 - p (complement of the estimated proportion)
E is the desired margin of error (0.02)
Plugging in the values, we have:
n = (1.75^2 * 0.5 * 0.5) / 0.02^2
n ≈ 2627
Therefore, the pollster should survey 2627 voters in order to be 96 percent confident that the true proportion of U.S. voters opposing capital punishment is estimated to within 0.02.
This sample size calculation ensures that the estimate of the true proportion will have a margin of error (E) of 0.02 or less, providing a high level of confidence (96 percent) in the accuracy of the estimate.
In conclusion, by using the formula for sample size estimation, the pollster should survey 2627 voters to achieve a 96 percent confidence level with a margin of error of 0.02 when estimating the true proportion of U.S. voters opposing capital punishment.
To know more about proportion refer here:
https://brainly.com/question/31548894
#SPJ11
Make a the subject of the formula v = u + at.
Hence, find the value of a when t = 4, u = 10 and v=50.
Step-by-step explanation:
v = u + at
v-u = at
a = (v -u)/t
When t = 4, u=10, v=50
a = (50-10)/4
a= 40/4
a = 10
Please Help Meeeee!!! Will Mark Brainliest!!!
Answer:
Part A: Yes. For every 10 employees, an increase of 80 products produced.
Part B: y = 8x + 120
Part C: Y-intercept indicates the number of products produced when there are 0 employees. The slope indicates the rate of increase of production with the number of employees
Step-by-step explanation:
Part A: 80 - 0 = 80 employees; 760 - 120 = 640 products. Therefore, 640/80 = 8 products per employee or 80 products per 10 employees
Part B: For y = mx + c ,
m = (Y1 - Y0)/(X1 - X0) = (760 - 120)/(80 - 0) = 8
c = Y-intercept, when X = 0. Therefore c = 120
a basic variable in a linear system is a variable that corresponds to a pivot column in the coefficient matrix.T/F
True - the statement says that a basic variable corresponds to a pivot column in the coefficient matrix. From the definition of basic variables, basic variables correspond to the columns that have a leading 1's (pivot columns).
A mathematical system model based on the use of a linear operator is known as a "linear system" in systems theory. In contrast to nonlinear cases, linear systems often display considerably simpler traits and attributes.
In linear systems, the variables are really only multiplied with constants and then added together; they are never multiplied by each other. In order to express both static and dynamic relationships between variables, linear systems are used.
Something relating to a line is linear. To build a line, all of the linear equations are used. Any equation that doesn't result in a straight line is considered as non. It has a variable slope value and appears as a curve on a graph.
A linear system is one in which both the superposition and homogeneity principles hold true.
For such more questions on Linear system:
brainly.com/question/27664510
#SPJ4
The sides of a rectangle are in the ratio 1:2. If the rectangle has an area of 578 in2, find the dimensions of the rectangle and the perimeter
Answer:
find the width and length
Step-by-step explanation:
What is the slope of the following equation? y=3x+1
Answer:
Slope = 3
Explanation:
If we have an equation of the form
\(y=mx+b\)then m is the slope and b is the y-intercept.
Now in our case, the equation we have is
\(y=3x+1\)Here we identify m = 3. Meaning the slope of the equation is 3.
What is the perimeter of a pentagon ABCDE with given vertices at A(4, -2), B(4, 10), C(7, 10), D(15, 4), E(7, -2)
Answer:
38 units
Step-by-step explanation:
You want the perimeter of pentagon ABCDE with vertices at A(4, -2), B(4, 10), C(7, 10), D(15, 4), E(7, -2).
PerimeterThe perimeter of a plane figure is the sum of the lengths of its sides.
Vertical, Horizontal sidesBy counting grid squares, or subtracting coordinates, you can find the lengths of the vertical and horizontal segments easily:
AB = 12, BC = 3, EA = 3
Diagonal sidesThe lengths of the diagonal segments can be found using the distance formula or your knowledge of Pythagorean triples. Counting grid squares (or subtracting coordinates), you see that each diagonal side has a vertical distance of 6 and a horizontal distance of 8. These correspond to twice the lengths of the sides in a 3-4-5 triangle, so you know the diagonal length is twice the hypotenuse: 2·5 = 10.
The Pythagorean theorem, or the distance formula, will tell you the same thing:
c² = a² +b² . . . . . . Pythagorean theorem for sides a, b, hypotenuse c
c = √(a² +b²)
diagonal length = √(6² +8²) = √100 = 10
Then the remaining two sides are ...
CD = 10, DE = 10
ApplicationThe perimeter is ...
perimeter = AB +BC +CD +DE +EA
= 12 +3 +10 +10 +3 = 38 . . . units
The perimeter of pentagon ABCDE is 38 units.
pls answers asap!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
i know that the first one is correct because its infinite but I'm sorry i don't know the second one. : ( (try the increasing -&,&) tho im not sure
Step-by-step explanation:
graph each function y=-x2+5
Answer:
on the y axis 5 then down 1 over 1 on both sides
Step-by-step explanation:
Express your answer as a polynomial in standard form.
Answer:
f(x) = 5x - 4
g(x)=x²-3x - 11
Find: (fog)(x)
Submit Answer
Answer:
(f o g)(x) =
5x²-15x - 51
Step-by-step explanation:
(f o g)(x) means to wad up g(x) and stuff it into the place of x in f(x).
(f o g)(x)
means f( g(x) )
Here's f(x)
f(x) = 5x - 4
If you were calculating f(2) you would put a 2 in place of x. Or f(18) you would put 18 in place of the x. In this case we will cram the entirety of
x²-3x - 11 into the place of x.
f(x) = 5x + 4
Let's make a lot of room for g(x).
f(x) = 5___x_____ + 4
Okay, here we go:
f(g(x))
= 5(x²-3x - 11) + 4
See how we replace the x in f(x) with the whole entire g(x).
Now we'll simplify because they asked for standard form.
f(g(x))
= 5(x²-3x - 11) + 4
Use distributive property.
= 5x²-15x - 55 + 4
Combine like terms.
= 5x²-15x - 51
(f o g)(x) =
f( g(x) ) = 5x²-15x - 51
A plane traveled 5525 miles with the wind in 8.5 hours and 4505 miles against the wind in the same amount of time. Find the speed of the plane in still air and the speed of the wind. The speed of the plane in still air is ____(hours.miles.mph) (Simplify your answer.)
Answer:
590mph
Step-by-step explanation:
Speed with wind = 5525÷ 8.5
= 650mph
speed against wind = 4505÷8.5
= 530mph
speed without wind = (650mph+530mph)÷2
= 590mph
At a coffee shop, two sizes of coffee are sold. A medium coffee costs $3, and a large coffee costs $5. Write an equation that represents the relationship between the number of medium coffees sold, x, and the number of large coffees sold, y, in an hour where sales totaled $68.
The equation that represent the relationship of the coffees is 3x + 5y = 68.
How to represent situation with system of equation?At a coffee shop, two sizes of coffee are sold. A medium coffee costs $3, and a large coffee costs $5.
The equation that represent the relationship between the number of medium coffees sold, x, and the number of large coffees sold, y, in an hour where sales totalled $68 is as follows:
where
x = number of medium coffees soldy = number of large coffees soldTherefore, the equation is as follows:
3x + 5y = 68
learn more on equation here:https://brainly.com/question/14177953
#SPJ1
if a probability of a single birth resulting in a boy is 51%, what is the probability of a single birth resulting in a girl? (
The probability of a single birth resulting in a girl if the probability of a single birth resulting in a boy is 51% is 49%
Probability is the measure of the likelihood of an event occurring. The probability of an event occurring ranges from 0 to 1. If an event is impossible, the probability of its occurrence is 0, and if the event is certain to occur, the probability is 1. The probabilities of the complement of an event equal one minus the probability of the event. For instance, the probability of the complement of an event A, denoted as A', is 1 - P(A). If the probability of an event A is P(A), then the probability of the complement of A is 1 - P(A).
Here, the probability of a single birth resulting in a boy is 51%. Therefore, the probability of a single birth resulting in a girl is the complement of this event, which is 49%. Hence, the main answer is that the probability of a single birth resulting in a girl if the probability of a single birth resulting in a boy is 51% is 49%.
Learn more about probability: https://brainly.com/question/25839839
#SPJ11
PLEASE HELP ME FAST!!!!!
Answer:
29/36pi radians
240 degrees
Step-by-step explanation:
pi = 180
145/180pi = 29/36pi radians
4/3*180 = 240 degrees
Find the exact value of cos ( - ). 9л a. 1/2 b. C. √√3 d. e. - -155-15 2 √√3 2
The correct answer is e. (√3 - 1)/2.
To find the exact value of cos(-π/9), we can use the symmetry property of the cosine function.
The cosine function has a property called evenness, which means that cos(-θ) = cos(θ) for any angle θ.
In this case, we have cos(-π/9). Since the angle is negative, we can rewrite it as -(-π/9), which simplifies to π/9.
So, cos(-π/9) is equal to cos(π/9).
Now, we can determine the exact value of cos(π/9) using trigonometric identities or a calculator.
The exact value of cos(π/9) is (√3 - 1)/2.
Therefore, the correct answer is e. (√3 - 1)/2.
Learn more about functions from
https://brainly.com/question/11624077
#SPJ11
Simplify: a(a+b+2)- 2(a²+ab+2a)+3(a+ab)
Step-by-step explanation:
I think you are 100 percent Clear.Thanks
the standard recommendation for automobile oil changes is once every 5000 miles. a local mechanic is interested in determining whether people who drive more expensive cars are more likely to follow the recommendation. independent random samples of 45 customers who drive luxury cars and 40 customers who drive compact lower-price cars were selected. the average distance driven between oil changes was 5187 miles for the luxury car owners and 5214 miles for the compact lower-price cars. the sample standard deviations were 424 and 507 miles for the luxury and compact groups, respectively. assume that the two population distributions of the distances between oil changes have the same standard deviation. construct a 95% confidence interval for the difference in the mean distances between oil changes for all luxury cars and all compact lower-price cars.
The 95% confidence interval for the difference in the mean distances between oil changes for all luxury cars and all compact lower-price cars is (-94.86, 310.86) miles.
To construct the confidence interval, we use the two-sample t-test with equal variances assumption. We calculate the pooled standard deviation, which is a weighted average of the sample standard deviations based on their degrees of freedom. Then, we compute the standard error of the difference in means using the pooled standard deviation and the sample sizes.
We find the t-value using a t-distribution table with (n1+n2-2) degrees of freedom and a significance level of 0.05. Finally, we construct the confidence interval by adding and subtracting the product of the t-value and the standard error from the difference in sample means. Since the confidence interval includes zero, we conclude that there is no significant difference in the mean distance driven between oil changes for luxury and compact cars.
Therefore, we can infer that the cost of the car is not a significant factor in determining whether people follow the standard recommendation for automobile oil changes.
Learn more about Confidence Interval:
brainly.com/question/13067956
#SPJ11
A landscaper wants to find the answer to the question "How much time do people in Raleigh, North Carolina, spend doing yard work in one week?" He asks the owners of all 120 houses in a Raleigh neighborhood. Which best describes the accuracy of the results of the survey? The survey results will be inaccurate because lawns in one neighborhood do not represent all types of lawns in a large city. The survey results will be inaccurate because the entire population of Raleigh should have been surveyed. The survey results will be accurate because the sample represents the population and the population is the target of the survey. The survey results will be accurate because the sample size was large enough to represent the population.
Answer:
A- The survey results will be inaccurate because lawns in one neighborhood do not represent all types of lawns in a large city.
Step-by-step explanation:
smile:)