K.Brew sells a wide variety of outdoor equipment and clothing. The company sells both through mail order and via the internet. Random samples of sales receipts were studied for mail-order sales and internet sales, with the total purchase being recorded for each sale. A random sample of 18 sales receipts for mail-order sales results in a mean sale amount of $74.90 with a standard deviation of $21.75. A random sample of 9 sales receipts for internet sales results in a mean sale amount of $87.30 with a standard deviation of $19.75. Using this data, find the 95% confidence interval for the true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases. Assume that the population variances are not equal and that the two populations are normally distributed.

Step 1 of 3: Find the point estimate that should be used in constructing the confidence interval.

Step 2 of 3: Find the margin of error to be used in constructing the confidence interval. Round your answer to six decimal places.

Step 3 of 3: Construct the 95% confidence interval. Round your answers to two decimal places.

Answers

Answer 1

Answer:

Step-by-step explanation:

Step 1. The point estimate is the difference between the the mean amount of mail-order purchases and the mean amount of internet purchases. It becomes

74.9 - 87.3 = - 12.4

Step 2. The formula for determining margin of error is expressed aa

Margin of error = z√(s1²/n1 + s2²/n2)

Where

z = z score

s1 = sample standard deviation for data 1

s2 = sample standard deviation for data 2

n1 = number of samples in group 1

n2 = number of samples in group 2

For a 95% confidence interval, the z score is 1.96

From the information given,

s1 = 21.75

n1 = 18

s2 = 19.75

n2 = 9

z√(s1²/n1 + s2²/n2) = 1.96√(21.75²/18 + 19.75²/9) = 1.96 × 8.343

= 16.35

Step 3. Confidence interval = (x1 - x2) ± z√(s²/n1 + s2²/n2)

95% Confidence interval = - 12.4 ± 16.35


Related Questions

What is the square root of 7/9?

Answers

Answer:

  (√7)/3 ≈ 0.881917

Step-by-step explanation:

  [tex]\sqrt{\dfrac{7}{9}}=\dfrac{\sqrt{7}}{\sqrt{9}}\\\\=\boxed{\dfrac{\sqrt{7}}{3}\approx 0.881917}[/tex]

In the figure below, which term best describes point T?

Answers

Answer:

A

Step-by-step explanation:

What is the length of AC? PLEASE HELP ASAP WILL GIVE BRAINLIEST TY

Answers

Answer:

2.33 units

Step-by-step explanation:

[tex]\tan 25\degree =\frac{AC}{5}\\\\0.46630 = \frac{AC}{5}\\\\AC = 0.46630 \times 5\\AC =2.3315\\AC = 2.33 \: units[/tex]

please hurry!! 34 + 3 ⋅ 5 = ____. (Input only whole numbers.) Numerical Answers Expected! Answer for Blank 1:

Answers

Answer:

49

Step-by-step explanation:

First multiply 3 x 5.Which will give you 15.Then add 34 and 15 which will give you 49.

Answer:

49

Step-by-step explanation:

3 x 5 = 15

15+34 = 49

Math Help!!! ASAP!! I will give you brainliest!!

Answers

Answer:

Step-by-step explanation:

true true false

Two math students were asked to write an exeponential growth equations that had a starting value of 300 and a growth rate of 2%. Pierre thinks the answer is y=300(1.02)^x and Scott thinks that the answer is y=300(1.2)^x. Are either of them right and why?

Answers

Answer:

Pierre is right.

Step-by-step explanation:

A growth rate of 2% means that the values is increasing by 0.02 each year so the multiplying factor is 1.02.

Pierre is correct y = 300(1.02)^x.

Scotts  answer 1.2 = a growth rate of 20%.

What is the fractionation of X2 - 6X + 5

Answers

Answer:

  (x -1)(x -5)

Step-by-step explanation:

We recognize that 6 is the sum of the factors of 1·5, so we can write the factorization as ...

  x^2 -6x +5 = (x -1)(x -5)

_____

The product of factors will be ...

  (x +a)(x +b) = x^2 +(a+b)x +ab

So, the binomial constants "a" and "b" are factors of the trinomial constant that have a sum equal to the coefficient of the linear term. Here, those are factors of +5 that have a sum of -6. The factors of interest are -1 and -5: 5 = (-1)(-5); -6 = (-1) +(-5).

Which of the following is the image of C after a rotation of 180° about the origin?
A. (-5,2)
B. (-5, -2)
C. (-2,5)

Answers

Answer:

A: (-5,2)

Step-by-step explanation:

algebraically, a 180 rotation about the origin switches the original coordinates of (x,y) to (-x,-y), so the answer would be (-5,2) after plugging the numbers into this formula

When Jonas becomes the Receiver of Memory, he gets a rule that he may not tell his dreams. He wants to know how many of his 505050 classmates have the same rule. He asks 555 friends from his class whether they may tell their dreams. Of those, 444 say that they may.

Answers

Answer:

101010 classmates can't tell their dreams.

Step-by-step explanation:

I'm not sure what the question is, but if it is an average thing than 444 of 555 is 80 percent, so if that is what it wants 404040 of the students can share their dreams, and 101010 can't.

Hope this helps!

Brainliest for anyone if they get this CORRECT.

Answers

answer is D7/2

hope it helps!!!!!!!!!!!!!!!!!!!!!!


Elliot is simplifying a radical. His work is shown


Which statement best applies to Elliot's mathematical work?
A. The equality V64 = 4.16 is incorrect or invalid.
B. Removing the 4 from under the radial in the second step is incorrect or invalid
C. The work shown above is correct; however, 2V16 can be simplified further.
D. The work shown above is correct; and 2V16 cannot be simplified further

Answers

Answer:

  C. correct, but can be further simplified

Step-by-step explanation:

Elliot's work is correct, but he apparently failed to recognize that 64 = 8². The radical could be simplified to ...

  √64 = 8

Answer:

c

Step-by-step explanation:

got it right

Find z1z2 if z1 = 3(cos37° + isin37°) and z2 = 2/3(cos53° + isin53°).

Answers

Answer:

[tex]z_{1}\cdot z_{2} = 2\cdot (\cos 90^{\circ} + i \cdot \sin 90^{\circ})[/tex]

Step-by-step explanation:

Both variable can be rewritten into polar form:

[tex]z_{1} = 3\cdot e^{i\cdot 0.205\pi}[/tex] and [tex]z_{2} = \frac{2}{3}\cdot e^{i\cdot 0.294\pi}[/tex]

The complex product is equal to:

[tex]z_{1}\cdot z_{2} = (3)\cdot \left(\frac{2}{3}) \cdot e^{i\cdot (0.205\pi+0.294\pi)}[/tex]

[tex]z_{1}\cdot z_{2} = 2 \cdot e^{i\cdot 0.499\pi}}[/tex]

The resultant expression in rectangular form is:

[tex]z_{1}\cdot z_{2} = 2\cdot (\cos 90^{\circ} + i \cdot \sin 90^{\circ})[/tex]

Answer:

The correct question is:

Find [tex]z_{1}.z_{2}[/tex] if [tex]z_{1}= 3(cos37 + isin37)[/tex] and [tex]z_{2}= \frac{2}{3} (cos53 + isin53)[/tex].

(Note: the angles mentioned in the equations above are in degrees)

The answer is [tex]z_{1}.z_{2}= 2i[/tex]

Step-by-step explanation:

[tex]z_{1}.z_{2}= 3(cos37 + isin37)* \frac{2}{3} (cos53 + isin53)[/tex]

[tex]z_{1}.z_{2}= (3cos37 + 3isin37)* (\frac{2}{3} cos53 + \frac{2}{3}isin53)[/tex]

[tex]z_{1}.z_{2}= 3cos37*\frac{2}{3} cos53 + 3cos37*\frac{2}{3}isin53+3isin37*\frac{2}{3} cos53+3isin37*\frac{2}{3}isin53[/tex]

[tex]z_{1}.z_{2}= 0.961+1.275i+0.724i-0.961[/tex] (Because [tex]i*i=i^{2}=-1[/tex] & [tex]i=\sqrt{-1}[/tex])

[tex]z_{1}.z_{2}= 0.961+1.275i+0.724i-0.961[/tex]

[tex]z_{1}.z_{2}= 2i[/tex]

??????????????????????

Answers

Answer:

The answer you put is correct.

Step-by-step explanation:

It is B.

Answer:

[tex]882\pi[/tex]

Step-by-step explanation:

The formula for the volume of a cylinder is [tex]\pi r^2 h[/tex], where r is the radius and h is the height of the cylinder. Therefore, the volume of this cylinder is [tex]\pi \cdot 7^2 \cdot 18=882\pi[/tex] cubic feet. Hope this helps!

PLEASE HELP WHEN YOU SEE THIS

Answers

Answer:

~ m∠1 = 35 degrees ( ° ) ~

Step-by-step explanation:

1. This pair of intersecting lines form four pairs of supplementary angles, which may be one approach to this problem.

2. This first pair includes the 145 degree angle, which we may assign as 4, and angle 1, the second being 2 and 1, 2 and 3, and 3 and 145 degrees.

3. If we were to consider the first pair of supplementary angles, it would be that 145 + m∠ 1 = 180, or ⇒ m∠1 = 180 - 145 = 35 degrees ( ° )

4. To confirm that this is the right answer, let us prove that with this measure of ∠1 the intersecting lines = 360 degrees, as after all they form a circle.

5. By Vertical Angles Theorem: m∠2 = m∠4, and m∠3 = m∠1

6. It is provided that m∠4 = 145 degrees ( ° ) and m∠1 = 35 degrees ( ° ). Given such let us substitute these values into Step #5, as such      ⇒     m∠2 = 145°, and m∠3 = 35°

7. The sum of the angles are known to 360 degrees, as provided previously, such that m∠1 + m∠2 + m∠3 + m∠4 = 360°, ⇒ 35 + 145 + 35 + 145 = 360, ⇒ 360 = 360

8. This proves that the m∠1 = 35 degrees ( ° )

help me plss to find the area​

Answers

Answer:

A=88 square units

Step-by-step explanation:

A=B x H

A= 11 x 8

A=88 square units

how many thousands make 5crore​

Answers

Answer:

50,000 thousands make a crore.

Step-by-step explanation:

One crore (1,00,00,000) is equal to one hundred lakh (10,000 × 1,000). Thus, 10,000 thousands make a crore.

The manufacturer of pencils spends $0.05 to make each pencil and sells them for
0.25. The manufacturer also has fixed costs each month of $2000. Find the cost function C when x pencils are manufactured.

Answers

Answer: C(x) = 2000+ 0.05 x

Step-by-step explanation:

Hi, to answer this question we simply have to apply the next formula:

Cost (C) = fixed cost + (cost per pencil x number of pencils)

Since:

Fixed cost: $2000

Cost per pencil : $0.05

Replacing with the values given:

C(x) = 2000+ 0.05 x

Where x is the number of pencils manufactured.

Feel free to ask for more if needed or if you did not understand something.

[ Cuiu be made.
There are 24 boys for every 36 girls (24:36 ratio)
There are
boys for every
girls
try
Type in an equivalent ratio of boys and girls.

Answers

Answer:

24/36 = 12 x 2/12 x 3 = 2/3.

Step-by-step explanation:

3/4 x 1/4

next problme: 3/5 x 1/5


100 pts

Answers

Answer:

0.1875 and 0.12

Step-by-step explanation:

3/4x1/4 is 0.1875. 3/5 x 1/5 is 0.12

Answer:

1)0.1875

2)0.12

Step-by-step explanation:

Please help ASAP! Will give BRAINLIEST! Please read the question THEN answer correctly! No guessing.

Answers

Answer:

x = -3  ±sqrt(27)

Step-by-step explanation:

x^2 +6x = 18

Take the coefficient of x

6

Divide by 2

6/2 =3

Square it

3^2 = 9

Add this to each side

x^2 +6x+9 = 18+9

6/2 or 3 is what is inside the (x+   )^2 on the left

(x+3) ^2 = 27

Take the square root of each side

sqrt((x+3) ^2) = ±sqrt(27)

x+3 = ±sqrt(27)

Subtract 3 from each side

x+3-3 = -3  ±sqrt(27)

x = -3  ±sqrt(27)

THIS IS MATH WORK AND IS VERY CONFUSING
I NEED HELP PLEASE
ASAP PLEASE
(Could you show work too thanks :D)

Answers

Step-by-step explanation:

1.

   First blank: total amount of outcomes

2.

   since there's four possible outcomes: (Head-Head, Head-Tail, Tail-Head, and Tail-Tail) Mason should expect to win 1/4 of the time, or roughly 50 times.

3.

   a) F

   b) F

   c) T

   d) T

   e) T

    f) T

4.

17/36, because 17 of the answers are greater than 10 and there are 36 total answers.

 

Sorry I didn't answer all of them, hopefully this still helps!

Goodluck with your schoolwork/homework!

--------------------------------------------------------------

Apologies in advance for any errors/bad explanations.

1/8 cups + what ? Makes 1 1/3 cups

Answers

Answer:

 1  5/24 cups

Step-by-step explanation:

We conduct a study to determine whether the majority of community college students plan to vote in the next presidential election. We choose a significance level of 0.05. We survey 650 randomly selected community college students and find that 54% of them plan to vote. The P-value is 0.02. H0: 50% of community college students plan to vote in the next presidential election. Ha: More than 50% of community college students plan to vote in the next presidential election. What can we conclude

Answers

Answer:

we can conclude that more than 50% of community college students plan to vote in the next presidential election

Step-by-step explanation:

Decision Rule

If;

P-value > significance level --- accept Null hypothesis

P-value < significance level --- reject Null hypothesis

Z score > Z(at 95% confidence interval) ---- reject Null hypothesis

Z score < Z(at 95% confidence interval) ------ accept Null hypothesis

Null hypothesis H0: 50% of community college students plan to vote in the next presidential election

H0: p = 0.50

Ha: More than 50% of community college students plan to vote in the next presidential election

Ha: p > 0.50

P-value = 0.02

From the decision rule;

Since the p-value for this study is less than the significance level.

0.02 < 0.05

So, we reject the null hypothesis, there is enough evidence to reject the null hypothesis. We thereby accept the alternative hypothesis.

Therefore, we can conclude that more than 50% of community college students plan to vote in the next presidential election

if you know the area How would you find the diameter of a circle?

Answers

Step-by-step explanation:

formular of area circle = pi*

[tex] {? \\ radius}^{2} [/tex]

=> radius =

[tex] \sqrt{area \div pi } [/tex]

diameter = 2* radius.hope this help


(13 – 6)^2 (5 + 2)^2÷(5 – 2)^3

Answers

Answer:

88 25/27

Step-by-step explanation:

(13 – 6)^2 (5 + 2)^2÷(5 – 2)^3

PEMDAS

Parentheses first

(7)^2 (7)^2÷(3)^3

Then exponents

49*49 ÷27

Then multiply and divide from left to right

2401÷27

2401/27

88 25/27

88.92592593

Answer:

Step-by-step explanation:

(7)^2(7)^2 / (3)^3

49*49 / 27

2401/27

88 25/27

Let a = 60. What is the value of a ÷ 5? equation

Answers

Answer:

12

Step-by-step explanation:

Just substitute 60 for a and divide it by 5

Ta Da!!





Consider that point A is reflected across the x-axis. What is the distance between point A and the point of its reflection?

Answers

Answer:

It would be 2 x the absolute value of the y coordinate.

Step-by-step explanation:

Example:

(5,-3)

Absolute value of y-coordinate is 3 and distance would equal 2 x 3 = 6 units apart.

What is the slope for the linear function y=3x-4

Answers

Answer:

3

Step-by-step explanation:

This is written in the form

y= mx+b

where m is the slope and b is the y intercept

3 is the slope and -4 is the y intercept

Solve (3x+7)=4x for x

Answers

Answer:

x=7

Step-by-step explanation:

(3x+7)=4x

Subtract 3x from each side

(3x+7) -3x=4x-3x

7 = x

Please help asap! Will give brainliest! Please read the question then answer correctly! No guessing.

Answers

Answer: C

Step-by-step explanation:

[tex]x^2+4x-21\\(x+7)(x-3)[/tex]

Answer: The correct answer is C.

Step-by-step explanation: If you factor the equation using the AC method, you will get this answer. Multiply A by C. For example, you would multiply 4 by 5 to get 20. List the factors of your answer from step two. That is, list pairs of numbers that you could multiply to come up with that answer. For instance, in the case of 20, you would have the following factors: (1, 20), (2, 10), (4, 5).

Find a pair of numbers among the factors that adds up to the B term in the equation. For this example, you must find a pair that adds up to 9. Therefore, you would isolate the pair (4, 5).

Replace the middle term (the B term) with the two numbers from the pair, along with the original variable that went with the B term. For example, you would write: 4x^2 + (4+5)x + 5 = 4x^2 + 4x + 5x + 5.

Group the first two terms and the last two terms together as such: (4x^2 + 4x) + (5x + 5).

Simplify the equation by finding terms that are common for each side. For instance, you would simplify (4x^2 + 4x) + (5x + 5) to 4x(x + 1) + 5 (x + 1). This would further simplify to (4x + 5) (x + 1).

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