Land's Bend 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 11 sales receipts for mail-order sales results in a mean sale amount of $79.00 with a standard deviation of $18.25. A random sample of 18 sales receipts for internet sales results in a mean sale amount of $96.70 with a standard deviation of $20.25. Using this data, find the 98% 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.

Answers

Answer 1

Answer:

−35.713332 ; 0.313332

Step-by-step explanation:

Given that:

Sample size, n1 = 11

Sample mean, x1 = 79

Standard deviation, s1 = 18.25

Sample size, n2 = 18

Sample mean, x2 = 96.70

Standard deviation, s2 = 20.25

df = n1 + n2 - 2 ; 11 + 18 - 2 = 27

Tcritical = T0.01, 27 = 2.473

S = sqrt[(s1²/n1) + (s2²/n2)]

S = sqrt[(18.25^2 / 11) + (20.25^2 / 18)]

S = 7.284

(μ1 - μ2) = (x1 - x2) ± Tcritical * S

(μ1 - μ2) = (79 - 96.70) ± 2.473*7.284

(μ1 - μ2) = - 17.7 ± 18.013332

-17.7 - 18.013332 ; - 17.7 + 18.013332

−35.713332 ; 0.313332


Related Questions

help me,,.,,.,.,,,,,..,,,,..

Answers

Answer:

90

Step-by-step explanation:

that's a right angle

Multiply the following using the vertical multiplication method:
x2 + 5x +1
x3x2 - 2x +4
O
A. 3x4 - 13x3 +3x2 + 18x + 4
B. 3x4 - x2 + 3x2 + x + 4
o
C. 3x4 + x2 + x2 +18x + 4
o
D. 3x4 +13x3 - 3x2 + 18x + 4

Answers

Answer:

a I think I might be a try it tell me if I am wrong

You are traveling down a country road at a rate of 95 feet/sec when you see a large cow 300 feet in front of you and directly in your lane. The cow is fearless, and staring you down. (Or perhaps she does not understand the gravity of the situation.) Regardless, if you simply hit your brakes, after t seconds, the car will be j(t) = 95t - 9t^2 feet from the point where the brakes were first applied.
1) Must you steer to avoid the cow, or can you rely solely on your brakes? Explain.
2) Graph J(t), j'(t), and j"(t) and Interpret their meanings in context.
3) Is there a time t after which the graphs in part (ii) probably do not accurately model the path of the car?
4) Write a piece-wise function using j(t) that would more accurately model the path of the car on the interval [0, 10], assuming the car did not move after it stopped. Sketch this graph and its derivative.

Answers

Answer:

1) You can rely solely on your brakes because when doing so the car will just travel 250ft from the point you hit your brakes till the point the car stopped completely, leaving you 50ft away from the cow.

2) See attached picture.

j(t) represents the distance from the point you hit the brake t seconds after you hit it in feet

j'(t) represents the velocity of the car t seconds after the brakes have been hit in ft/s.

j"(t) represents the acceleration of the car t seconds after the brakes have been hit in [tex]ft/s^{2}[/tex]

3) yes, any time after t=5.28 will not accurately model the path of the car since at that exact time the car will reach a velocity of 0ft/s and unless another force is applied to the car, then the car will not move after that time.

4) [tex]j(t)=\left \{ {{95t-9t^{2}; 0\le t<5.28s} \atop {250.69; 5.28s\leq t \leq 10s}} \right.[/tex]

[tex]j'(t)=\left \{ {{95-18t; 0\leq t<5.28s} \atop {0 ; 5.28s\leq t \leq 10s}} \right.[/tex]

(see attached picture for graph)

Step-by-step explanation:

1) In this part of the problem we need to find the time when the speed of the car is 0. Gets to a complete stop. For this we will need to take the derivative of the position function so we get:

[tex]j(t)=95t-9t^2[/tex]

[tex]j'(t)=95-18t[/tex]

and we set the first derivative equal to zero so we get:

95-18t=0

and solve for t

-18t=-95

[tex]t=\frac{95}{18}[/tex]

t=5.28s

so now we calculate the position of the car after 5.28 seconds, so we get:

[tex]j(5.28)=95(5.28)-9(5.28)^{2}[/tex]

[tex]j(5.28)=250.69ft[/tex]

so we have that the car will stop 250.69ft after he hit the brakes, so there will be about 50ft between the car and the cow when the car stops completely, so he can rely just on the breaks.

2) For answer 2 I take the second derivative of the function so I get:

[tex]j(t)=95t-9t^{2}[/tex]

[tex]j'(t)=95-18t[/tex]

j"(t)=-18

and then we graph them. (See attached picture)

j(t) represents the distance from the point you hit the brake t seconds after you hit it in feet

j'(t) represents the velocity of the car t seconds after the brakes have been hit in ft/s.

j"(t) represents the acceleration of the car t seconds after the brakes have been hit in [tex]ft/s^{2}[/tex]

3)  yes, any time after t=5.28 will not accurately model the path of the car since at that exact time the car will reach a velocity of 0ft/s and unless another force is applied to the car, then the car will not move after that time.

4) [tex]j(t)=\left \{ {{95t-9t^{2}; 0\le t<5.28s} \atop {250.69; 5.28s\leq t \leq 10s}} \right.[/tex]

[tex]j'(t)=\left \{ {{95-18t; 0\leq t<5.28s} \atop {0 ; 5.28s\leq t \leq 10s}} \right.[/tex]

(see attached picture for graph)

Find the missing angle

Answers

bro what angle I don't see one here so how we are able to solve this problem

Find the surface area of the rectangular prism.

HELP ME PLS ASAP PLS PLZ

Answers

Answer: 222 cm

Explanation: 9x3=27x2=54
7x3=21x2=42
7x9=63x2=126
54+42+126=222
The answer is 222 centimeters

Find the unknown value in the proportion. 3/5 = x/20. what is the value of
X?

Answers

The answer should be x=12

CL 6-153
In 2012 the average cost for a new midsized car was about
$31,000. New car prices tend to go up about 2% every year.
a. What is the multiplier for this situation?
b. If this trend continues, what will the cost be in 4 years?
c. Write an equation to calculate the cost in n years. What does
each of the factors in your equation represent?

Answers

Answer:

A) The multiplier for this situation is 0.02.

B) The cost in 4 years will be $ 33,555.39.

C) 31,000 x 1.02 ^ N = X

Step-by-step explanation:

Since in 2012 the average cost for a new midsized car was about $ 31,000, and new car prices tend to go up about 2% every year, to determine what is the multiplier for this situation, what will the cost be in 4 years if this trend continues and to write an equation to calculate the cost in n years the following calculations must be performed:

A)

31,000 x 2/100 = X

31,000 x 0.02 = X

Thus, the multiplier for this situation is 0.02.

B)

31,000 x 1.02 ^ 4 = X

33,555.39 = X

Thus, the cost in 4 years will be $ 33,555.39.

C)

31,000 x 1.02 ^ N = X

Here, N represents the number of years over which the price increase will be calculated, and X represents the price after that number of years.

Pls help this is due today! A circular plate has a circumference of 14p in. Find the area of the same plate.

Answers

Circumference is pi x diameter
So the diameter is 14
Area of a circle is pi x r^2
radius is half the diameter
so radius = 7
So pi x 7^2
= 49pi

Answer:

area = 153.86 in²

Step-by-step explanation:

Diameter = 14π / π = 14

radius = 1/2(14) = 7

area = π7² = 153.86 in²

An expression equivalent to -4(2k-6)

Answers

Answer:

-8k + 24

Step-by-step explanation:

Is your expression.

Question
Example
Step by Step
The endpoints of a side of rectangle ABCD in the coordinate plane are at A (2.11) and
B7, 1). Find the equation of the line that contains the given segment
The line segment is BC.
The equation is y =
llo

Answers

need more to answer

6. Missing data, nonrandom samples, and outlying observations True or False: If the data for an observation on either the dependent variable or one of the independent variables are missing at random, then the size of the random sample available from the population must be reduced, which reduces the estimator's precision and introduces a bias.

Answers

Answer:

False

Step-by-step explanation:

The answer to this question is false because the missing observation does not introduce bias to the estimator. But missing observations reduces the size of the sample that is available from the given population. Therefore reducing the precision of the estimators.

In conclusion, no bias is introduced because of missing observations so the answer is false.

Find the area of a circle with a diameter of 16.
Either enter an exact answer in terms of or use 3.14 for at
and enter your answer as a decimal.
units?
Help me

Answers

Answer:

A=200.96.

Step-by-step explanation:

A=3.14×16/2^2.

A=3.14×8^2.

A=3.14×64.

A=200.96 or A=201.

Write a function called Radians_To_Degrees which will convert an angle from Radians to Degrees. In your Lesson 06 script: a. convert 1.62 radians to degrees b. Convert pi/9 radians to degrees

Answers

Answer:

a) 92.9 degrees

b) 20 degrees

Step-by-step explanation:

Using the conversion factor;

180 degrees = pi radians

For 1.62 radians;

1.62 radians = x

pi radians = 180 degrees

Divide both expressions;

1.62/pi = x/180

pi * x = 1.62 * 180

pi * x = 291.6

x = 291.6/pi

x = 291.6/3.14

x = 92.9 degrees

Hence 1.62 radians is equivalent to 92.9 degrees

b) Recall that

pi radians = 180 degrees

pi/9 rad = y

Cross multiply

y * pi = 180pi/9

y = 180/9

y = 20 degrees

Hence pi/9 radians is equivalent to 20 degrees

4/15 x 6 in simplest form

Answers

Answer:

1.6

Step-by-step explanation:

4/15= 0.2666
0.2666 x 1.5996 ~ 1.6
so the answer is 1.6 :D

What is the equation of a line that has a slope of -3 and passes through the point (2,5)?
A y=-3x - 1
B. y=-3x +11
C.y= 2/5x -3
D. y=5/2x-3

Answers

Answer:

B

Step-by-step explanation:

the answer is B y=-3x+11

Almost done. I need help with this part

Answers

Answer:

[tex]\%Percent = 14.3\%[/tex]

Step-by-step explanation:

Required

15 is what percentage of 105

To do this, simply divide 15 by 105 multiplied by 100%.

So, we have:

[tex]\%Percent = \frac{15}{105} * 100\%[/tex]

[tex]\%Percent = \frac{15*100}{105}\%[/tex]

[tex]\%Percent = \frac{1500}{105}\%[/tex]

[tex]\%Percent = 14.3\%[/tex] --- approximated

15. Paula bought a ski jacket on sale for $20
less than half of its original price. She
paid $68 for the jacket. What was the
original price?

Answers

Answer:

Step-by-step explanation:

P/2-20=68, add 20 to each side

P/2=88, multiply each side by 2

P=$176

The original price was $176

WORTH 25 points!! NEED ASAP!! REALLY IMPORTANT

Answers

Answer:

V = (4.2)(7.5)·w

if w = 2 then V = 63 ft³

Step-by-step explanation:

V = l·w·h

V = (4.2)(7.5)(2)

V = 63

What is the equation of line d and c? What is the slope of line d and line c?​

Answers

Answer:

Step-by-step explanation:

I understand why this was kind tough

the slope of line d is infinite  and the slope of line c is zero

so line c 's  equation looks like  y = 3  ... it's kinda  confusing but  the line is always 3  so you could pick any x value and y = 3 still.  the equation y=3 doesn't rely on x at all to answer it.    But x is part of the "frame work" that is implied.    

line d  is  x = 3   , again , y is part of the "frame work" and implied that y doesn't matter in this equations, you always have x = 3 .. or a vertical line , btw. line d does NOT pass the vertical line test , and therefore isn't a function,  so the question is wrong, that d will have an equation,  b/c there is an implication that d is a function when you say "what is the equation to line d" that is must be a function. But in this case it's not.   hm :/  food for thought

ineeeddddddyoooouuuurrrrr hhhheeeellllpppp ppppllllssss

Answers

D. 36cm^3

Hope this helps!

Answer:

d. you just have to multiply everything

Help

Amelia's water bottle holds 4 pints, 2 cups. How many cups does Amelia's water bottle hold? Note: 1 pint = 2 cups
Group of answer choices

Answers

Answer: it hold 8 cups

Step-by-step explanation:

May I plz get brainlest

If she has 4 pints and 2 cups, and pints still needs converted, then multiply 4 by 2 to get the number of cups per pint. so she has 8+2 cups, or 10 cups in her water bottle

---

hope it helps

midsegment of a trapezoid find x​

Answers

Answer:

x = 7

Step-by-step explanation:

Based on the midsegment theorem of a trapezoid, thus:

NP = (JK + ML)/2

Substitute

45 = (3x + 11 + 10x - 12)/2

2*45 = 13x - 1

90 = 13x - 1

90 + 1 = 13x

91 = 13x

Divide both sides by 13

91/13 = x

7 = x

x = 7

round to the nearest 10th​

Answers

230 to the nearest 10 240

What is the value of n ?

Answers

Answer:

n=10

Step-by-step explanation:

5n-20=3n

-20=-2n

10=n

What is the area of the shaded region in the figure?

Answers

Answer:

look at the picture i sent please

Helpppppppppp sjsndkejsnsnsb

Answers

Answer:

18.8 fleck dickon Dunn dream fun deep

Identify the y-intercept of the graph below

Answers

Answer:

I want to say it's A

Step-by-step explanation:

the y-intercept is where the line crosses through the y-axis.

Find the measure of 2.
50 2.
1130
< 2 =
[?]

Answers

= 180° - 50°
= 130°

the answer is 130°

The lines below are parallel. If the slope of the green line is -2, what is the
slope of the red line?

Answers

Answer:

C. -2

Step-by-step explanation:

All parallel lines have the same slope

Evaluate each expression if m = 3 and n = 7. n to the power of 2 - 2m plz

Answers

Answer:

[tex]7^{2}[/tex] -2 * 3 is equal to 43

Step-by-step explanation:

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