A market research firm supplies manufacturers with estimates of the retail sales of their products from samples of retail stores. Marketing managers are prone to look at the estimate and ignore sampling error. A random sample of 36 stores this year shows mean sales of 53 units of a small appliance with a standard deviation of 12 units. During the same point in time last year, a random sample of 49 stores had mean sales of 41 units with standard deviation 6 units.

It is of interest to construct a 95 percent confidence interval for the difference in population means ?1??2, where ?1 is the mean of this year's sales and ?2 is the mean of last year's sales.

Enter values below rounded to three decimal places.

(a) The estimate is: _________ .

(b) The standard error is: ____________________ .

Answers

Answer 1

Answer:

The 95% confidence interval for the difference of means is (7.67, 16.33).

The estimate is Md = 12.

The standard error is sM_d = 2.176.

Step-by-step explanation:

We have to calculate a 95% confidence interval for the difference between means.

The sample 1 (this year's sales), of size n1=36 has a mean of 53 and a standard deviation of 12.

The sample 2 (last year's sales), of size n2=49 has a mean of 41 and a standard deviation of 6.

The difference between sample means is Md=12.

[tex]M_d=M_1-M_2=53-41=12[/tex]

The estimated standard error of the difference between means is computed using the formula:

[tex]s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{12^2}{36}+\dfrac{6^2}{49}}\\\\\\s_{M_d}=\sqrt{4+0.735}=\sqrt{4.735}=2.176[/tex]

The degrees of freedom are:

[tex]df=n_1+n_2-1=36+49-2=83[/tex]

The critical t-value for a 95% confidence interval and 83 degrees of fredom is t=1.989.

The margin of error (MOE) can be calculated as:

[tex]MOE=t \cdot s_{M_d}=1.989 \cdot 2.176=4.328[/tex]

Then, the lower and upper bounds of the confidence interval are:

[tex]LL=M_d-t \cdot s_{M_d} = 12-4.328=7.67\\\\UL=M_d+t \cdot s_{M_d} = 12+4.328=16.33[/tex]

The 95% confidence interval for the difference of means is (7.67, 16.33).


Related Questions

Use the zero product property to find the solutions to the equation x2 – 9 = 16.
x= -3 or x = 3
x= -6 or x = -3
Ox= -5 or x = 5
O x= 7 or x = 1

Answers

Answer:

x = ±5

Step-by-step explanation:

x^2 – 9 = 16

Add 9 to each side

x^2 – 9+9 = 16+9

x^2 = 25

Take the square root of each side

sqrt(x^2) = ±sqrt(25)

x = ±5

Answer:

[tex]x = 5 \: \: \: or \: \: x = - 5[/tex]

Step-by-step explanation:

[tex] {x}^{2} - 9 = 16 \\ {x}^{2} = 16 + 9 \\ {x}^{2} = 25 \\ x = \sqrt{25} \\ x = 5 \\ x = - 5[/tex]

hope this helps

brainliest appreciated

good luck! have a nice day!

In a Washington town, the charge for commerical waste collection is $694.55 for 5 tons of waste and $1098.56 for 8 tons of waste. (a) Find a linear formula for the cost, C. of waste collection as a function of the weight, w, in tons.

Answers

Answer:

[tex] m =\frac{1098.56-694.55}{8-5}= 134.67[/tex]

And we can find the intercept like this:

[tex] 694.55 = 134.67*5 +b[/tex]

[tex] b = 694.55 -673.35= 21.2[/tex]

And the equation would be given by:

[tex] C = 134.67 w + 21.2[/tex]

Step-by-step explanation:

For this case we want a function given by:

[tex] C = mw +b[/tex]

Where C is the cost, m the slope, w the weight and b the intercept.

We have the following info (w=5, C= 694.55) and (w=8, C=1098.56) and we can find the slope with this formula:

[tex] m =\frac{1098.56-694.55}{8-5}= 134.67[/tex]

And we can find the intercept like this:

[tex] 694.55 = 134.67*5 +b[/tex]

[tex] b = 694.55 -673.35= 21.2[/tex]

And the equation would be given by:

[tex] C = 134.67 w + 21.2[/tex]

A linear function is a function that changes at a constant rate.

The formula of the linear relationship is [tex]C = 134.67w + 21.2[/tex]

The given parameters are:

w = 5, C = 694.55 ---- Charges for 5 tonsw = 8, C = 1098.56 ---- Charges for 8 tons

Start by calculating the slope (m)

[tex]m = \frac{C_2 - C_1}{w_2 - w_1}[/tex]

This gives

[tex]m = \frac{1098.56 - 694.55 }{8- 5}[/tex]

Simplify

[tex]m = \frac{404.01}{3}[/tex]

This gives

[tex]m = 134.67[/tex]

The equation is then calculated as:

[tex]C = m(w -w_1) + w_1[/tex]

This gives

[tex]C = 134.67(w -5) + 694.55[/tex]

Expand

[tex]C = 134.67w -673.35 + 694.55[/tex]

[tex]C = 134.67w + 21.2[/tex]

Hence, the formula of the linear relationship is [tex]C = 134.67w + 21.2[/tex]

Read more about linear equations at:

https://brainly.com/question/14323743

A triangle with side lengths is 5,5,8 is what type of triangle

Answers

Answer:

isosceles triangle

Step-by-step explanation:

Write an equation of a line that passes through (-6, 1), parallel to y = 2x – 6.

Answers

Answer:

y = -1/2x - 2

Step-by-step explanation:

If it's parallel, that means that the slope is the opposite of the one in the given equation, meaning that 2 would be flipped and turned negative into -1/2.

Then, fill in the x and y values to get the y-intercept.

1 = -1/2(-6) + b

1 = 3 + b

-2 = b

So your answer is y = -1/2x - 2

Idaho is shaped like a triangle with a base of approximately 320 miles and a height of approximately 520 miles. Calculate the area of Idaho and write the answer in scientific notation

Answers

Answer:

8.32 × 10^4

Step-by-step explanation:

The formula for the area of a triangle is 1/2×b×h.

1/2(320)(520) = 83,2000

83,200 in scientific notation is 8.32 × 10^4

WILL GIVE BRAINLIEST 4 FIRST ANSWER.
When converted to speeds, which list is in order from slowest to fastest?

A: 17 miles in 2 minutes;
26 miles in 4 minutes;
33 miles in 6 minutes;
60 miles in 8 minutes

B: 17 miles in 2 minutes;
60 miles in 8 minutes;
26 miles in 4 minutes;
33 miles in 6 minutes

C: 33 miles in 6 minutes;
26 miles in 4 minutes;
60 miles in 8 minutes;
17 miles in 2 minutes

D: 60 miles in 8 minutes;
33 miles in 6 minutes;
26 miles in 4 minutes;
17 miles in 2 minutes

Answers

Answer:

c

Step-by-step explanation:

you should divide the distance on time

so

33/6=5.5

26/4=6.5

60/8=7.5

17/2=8.5

you can see answer in this order in c

Answer:

Answer:

c

Step-by-step explanation:

you should divide the distance on time

so

33/6=5.5

26/4=6.5

60/8=7.5

17/2=8.5

you can see answer in this order in c

Step-by-step explanation:

Which graph represents this equation-3x + 4y= -12

Answers

Answer:

C

Step-by-step explanation:

-3x+4y=-12

Add 3x to both sides:

4y=3x-12

Divide both sides by 4 to isolate y:

y=3/4x-3

This means that the line described has a slope of 3/4 and a y intercept of -3. The only graph that matches this is choice C. Hope this helps!

Answer: c

Step-by-step explanation:

Which ordered pair is the solution of the system of equations? 3x+2y=4, -2+2y=24, I need help Im very confused on how to solve this...

Answers

Answer:

x = -7.33        OR         x = [tex]\frac{-22}{3}[/tex]

y = 13

Step-by-step explanation:

→You can use the substitution method. First, make y by itself in (-2 + 2y = 24):

-2 + 2y = 24

2y = 26

y = 13

→Then, plug in 13 for y into the other equation:

3x + 2y = 4

3x + 2(13) = 4

3x + 26 = 4

3x = -22

x = -7.33        OR         x = [tex]\frac{-22}{3}[/tex]

A survey was sent out to re-evalute the proportion of people who play games on pc computers, as the last study on the topic had been gathered four years prior. This survey was done specifically to test the possibility that fewer people are playing games on pc computers. The previous study found that 81% of people were playing games on pc computers. The current study, with 861 participants, found that 53% of people who responded play on a pc computer.

Calculate the p-value and determine if we should accept or reject H0 under alpha = 0.05.

Answers

Answer:

[tex]z=\frac{0.53 -0.81}{\sqrt{\frac{0.81(1-0.81)}{861}}}=-20.943[/tex]  

The p value would be given by:

[tex]p_v =P(z<20.943)\approx 0[/tex]  

The p value is a very low value compared to the significance level given so then we have enough evidence to reject the null hypothesis and we can conclude that the true proportion is significantly less than 0.81

Step-by-step explanation:

Info given

n=861 represent the random sample

[tex]\hat p=0.53[/tex] estimated proportion of people who responded play on a pc computer

[tex]p_o=0.81[/tex] is the value that we want to test

[tex]\alpha=0.05[/tex] represent the significance level

z would represent the statistic

[tex]p_v[/tex] represent the p value

Hypothesis to test

We want to verify if the true proportion decreases from 81%, the system of hypothesis are.:  

Null hypothesis:[tex]p\geq 0.81[/tex]  

Alternative hypothesis:[tex]p < 0.81[/tex]  

The statistic is given by:

[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)  

Replacing the info given we got:

[tex]z=\frac{0.53 -0.81}{\sqrt{\frac{0.81(1-0.81)}{861}}}=-20.943[/tex]  

The p value would be given by:

[tex]p_v =P(z<20.943)\approx 0[/tex]  

The p value is a very low value compared to the significance level given so then we have enough evidence to reject the null hypothesis and we can conclude that the true proportion is significantly less than 0.81

Simplify the expression and then evaluate it for the given value of the variable:


(6−2x)+(15−3x) for x=−0.2
PLEASE HELP!!!!!!!!!!!!!!!!!

Answers

Answer:

-5x+2122

Step-by-step explanation:

There are no factors outside the parentheses that need to be distributed, so the parentheses can be simply dropped:

  6 -2x +15 -3x

The terms can be rearranged to put like terms next to each other:

  -2x -3x +6 +15

and the like terms can be combined.

  -5x +21 . . . . simplified expression

__

Put the value of x where x is, then do the arithmetic.

  -5(-0.2) +21 = 1 +21 = 22

Please answer this correctly

Answers

Answer:

0-19: Make it 4 units tall

20-39: Make it 2 units tall

40-59: Make it 5 units tall

60-79: Make it 3 units tall

80-99: Make it 1 unit tall

Step-by-step explanation:

0-19: 4, 6, 19, 19 (4 numbers)

20-39: 29, 38 (2 numbers)

40-59: 40, 41, 41, 57, 58 (5 numbers)

60-79: 62, 66, 73 (3 numbers)

80-99: 87 (1 number)

WILL GIVE BRAINLIEST! HURRY

Answers

Answer:

[tex]x = - 8[/tex]

Second answer is correct

Step-by-step explanation:

[tex] - 4(2x + 3) = 2x + 6 - (8x + 2) \\ - 8x - 12 = 2x + 6 - 8x - 2 \\ - 8x - 12 = - 6x + 4 \\ - 8x + 6x = 12 + 4 \\ - 2x = 16 \\ \frac{ - 2x}{ - 2} = \frac{16}{ - 2} \\ x = - 8[/tex]

hope this helps

Please answer this correctly

Answers

Answer:

A = 1/2 b*h

A = 24

b = 8

h = ?

24 = 1/2 * 8 * h

24 = 4h

h = 6

The height is 6 cm.

Hope this helps.

Let the velocity of a particle be given by v(t) = 2t+a.(a) Find the number a such that the average value of v(t) on the interval [0,1] is -2.(b) Using v(t) from part (a), find the distance traveled by the particle during the time period from [0,4].

Answers

Answer:

The velocity is v(t) = 2*t + a

a) we want to find the average velocity betwen t = 0 and t = 1.

We can do this as:

Average = (v(1) + v(0))/2 = (2*1 + a + 2*0 + a)/2 = 1 + a

b) now we want to find the total distance traveled in the time lapse from t = 0 to t = 4.

For this we can see the integral:

[tex]d = \int\limits^4_0 {2*t + a} \, dt = 4^2 + a*4 - 0^2 - a*0 = 4^2 + a*4 = 16 + a^2[/tex]

Terrance is 3.5 years older than Stephanie. Stephanie is 22.5 years old.

Answers

Answer:

Terrance is 25.5

Step-by-step explanation:

Answer:

Hello There. The correct answer is 26

T = 3.5 + 22.5 = 26

Hope It Helps!

Assume that SAT scores are normally distributed with mean mu equals 1518 and standard deviation sigma equals 325. If 1 SAT score is randomly selected, find the probability that it is greater than 1600. If 81 SAT scores are randomly selected, find the probability that they have a mean greater than 1600.

Answers

Answer:

[tex]P(X>1600)=P(\frac{X-\mu}{\sigma}>\frac{1600-\mu}{\sigma})=P(Z>\frac{1600-1518}{325})=P(z>0.252)[/tex]

And we can find this probability using the z score formula and the complement rule and we got:

[tex]P(z>0.252)=1-P(z<0.252) =1-0.599= 0.401 [/tex]

[tex] z =\frac{1600-1518}{\frac{325}{\sqrt{81}}}= 2.27[/tex]

And we can find this probability using the z score formula and the complement rule and we got:

[tex]P(z>2.27)=1-P(z<2.27) =1-0.988=0.012[/tex]

Step-by-step explanation:

Let X the random variable that represent the SAT scores of a population, and for this case we know the distribution for X is given by:

[tex]X \sim N(1518,325)[/tex]  

Where [tex]\mu=1518[/tex] and [tex]\sigma=325[/tex]

We want to find this probability:

[tex]P(X>1600)[/tex]

And we can use the z score formula given by:

[tex]z=\frac{x-\mu}{\sigma}[/tex]

Using this formula we got:

[tex]P(X>1600)=P(\frac{X-\mu}{\sigma}>\frac{1600-\mu}{\sigma})=P(Z>\frac{1600-1518}{325})=P(z>0.252)[/tex]

And we can find this probability using the z score formula and the complement rule and we got:

[tex]P(z>0.252)=1-P(z<0.252) =1-0.599= 0.401 [/tex]

For the other part we need to take in count that the distribution for the sampel mean if the sample size is large (n>30) is given by:

[tex]\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})[/tex]

And we can use the z score formula given by:

[tex]z=\frac{x-\mu}{\frac{sigma}{\sqrt{n}}}[/tex]

And replacing we got:

[tex] z =\frac{1600-1518}{\frac{325}{\sqrt{81}}}= 2.27[/tex]

And we can find this probability using the z score formula and the complement rule and we got:

[tex]P(z>2.27)=1-P(z<2.27) =1-0.988=0.012[/tex]

simplify (6^7)^3
will give brainlist

Answers

Answer:

The answer is D.

Step-by-step explanation:

You have to apply Indices Law,

[tex] { ({a}^{m}) }^{n} \: ⇒ \: {a}^{mn} [/tex]

So for this question :

[tex] { ({6}^{7}) }^{3} [/tex]

[tex] = {6}^{7 \times 3} [/tex]

[tex] = {6}^{21} [/tex]

Please answer this correctly

Answers

Answer:

d = 4

Step-by-step explanation:

Using the formula

A=pq/2

Dont for get to click THANKS

what is the positive solution for the equation

Answers

Answer:

x=3

Step-by-step explanation:

4x^2 - 36 = 0

Add 36 to each side

4x^2 -36 +36 = 0+36

4x^2 = 36

Divide each side by 4

4x^2/4 =36/4

x^2 = 9

Take the square root of each sdie

sqrt(x^2) = ±sqrt(3)

x = -3,+3

We want the positive square root

x=3

Express the following ratio in its simplest form.
4:12

Answers

Answer:

1:3

Step-by-step explanation:

divide 4 ...............

.............

ps: idk the explanation

A man spend 3/5 of his money and has$ 90 left . how much did he have initially​

Answers

Answer:

225 I believe because if he has $90 that is 2/5 so add another 90 whitch is 2/5 as well and divide 90 by 2 and to get 45 which all adds up to 225

Write the number one and three quarter million in figures.

Answers

Answer 1750000

Step-by-step explanation:

The number "one and three-quarter million" can be written in figures as 1,750,000.

Given the number one and three quarter million.

"One" represents the digit 1.

"Three-quarter" means three-fourths or 3/4.

In decimal form, this fraction is 0.75.

"Million" signifies a value of 1,000,000.

To represent this number in figures, we combine these components:

We start with the digit 1, representing "one."

Then we append the value 750,000, which corresponds to "three-quarter million."

Combining these two parts, we have 1,750,000.

Therefore, "one and three-quarter million" can be written in figures as 1,750,000.

To learn more on Number system click:

https://brainly.com/question/22046046

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Simplify (1+√3) (2-√3).

Answers

Answer:

[tex] \sqrt{3} - 1[/tex]

Step-by-step explanation:

[tex](1 + \sqrt{3} )(2 - \sqrt{3} ) \\ 2 - \sqrt{3} + 2 \sqrt{3} - 3 \\ = \sqrt{3} - 1[/tex]

what two numbers add to -7 and multiply to -60

Answers

Answer:

The answer would be 5 and -12

Find the balance at the end of 4 years if $10000 is deposited at a rate of 1.5% simple interest

Answers

Answer:

$9400

Step-by-step explanation:

1.5x4=6%

100-6=94

0.94x10000=9400

Multiply or divide as indicated.
10x^5 divide 2x^2

Answers

Answer:

5x^3(to the power of 3)

Step-by-step explanation:

10x^5/2x^2

divide the 10/2 like normal to get 5

x^5/x^2 (subtract the powers 5-2 when dividing powers)

you would get 5x^3

Seven students were surveyed on the number of hours of TV they watch each week. The results are shown below.
8, 12, 13, 15, 16, 17, 17
What is the mode of the data set?
7
14
15
17

Answers

the correct answer is 17

calculate the
Simple interest on a
7,500,00 for 4 years
at 4½
per
annum​

Answers

Step-by-step explanation:

S.i =principal x rate x time/100

7,50000x4x4.5/100

13500000/100

135000

What should be done to both sides of the equation in order to solve w - 9 1/2 = 15?

Answers

Answer:

Solve for  

w

by simplifying both sides of the equation, then isolating the variable.

Exact Form:

w

=

49

2

Decimal Form:

w

=

24.5

Mixed Number Form:

w

=

24

Answer:

24

Step-by-step explanation:

not sure help please​

Answers

Answer:

The area of a trapezoid is 1/2 (b₁ + b₂) * h where b₁ and b₂ are the bases and h is the height. The answer is 1/2 * (3 + 4) * 1 = 3.5.

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