In a random sample of 8 ​people, the mean commute time to work was 35.5 minutes and the standard deviation was 7.4 minutes. A 90​% confidence interval using the​ t-distribution was calculated to be (30.5,40.5). After researching commute times to​ work, it was found that the population standard deviation is 9.3 minutes. Find the margin of error and construct a 90​% confidence interval using the standard normal distribution with the appropriate calculations for a standard deviation that is known. Compare the results.

Answers

Answer 1

Answer:

Margin of Error = 5.4088 ;

Confidence interval = (30.1 ; 40.9)

Interval estimate are almost the same

Step-by-step explanation:

Given that :

Population standard deviation, σ = 9.3

Sample size, n = 8

Xbar = 35.5

Confidence level = 90%

The confidence interval:

Xbar ± Margin of error

Margin of Error = Zcritical * σ/sqrt(n)

Zcritical at 90% = 1.645

Margin of Error = 1.645 * 9.3/sqrt(8) = 5.4088

Confidence interval :

Xbar ± Margin of error

35.5 ± 5.4088

Lower boundary = (35.5 - 5.4088) = 30.0912 = 30.1

Upper boundary = (35.5 + 5.4088) = 40.9088 = 40.9

(30.1 ; 40.9)

T distribution =. (30.5 ; 40.5)

Normal distribution = (30.1, 40.9)


Related Questions

Help- this is also due tomorrow-

Answers

45???? dont u just subtract 180 by that then get the missing angle?

Answer:

46

Step-by-step explanation:


Find dy/dx
for 4 tan^2x - xy^2= sin2y by using implicit differentiation

Answers

Answer:

Y=bx+c

Step-by-step explanation:

That should be right

Answer:

Y=bx+c

Step-by-step explanation:

An equilateral triangle has a side length of 10 units. What is it’s area?

Answers

Answer:

[tex]25\sqrt{3}=43.3\ \mathrm{units}[/tex]

Step-by-step explanation:

Area of a triangle = [tex]\frac{1}{2}ab\textrm{sin}(\theta)[/tex] where [tex]a[/tex] and [tex]b[/tex] are the sides of the triangle and [tex]\theta[/tex] is the angle between those two sides.

The side length are 10, and since its an equilateral triangle, the angle is 60 degrees. Thus, the area becomes [tex]\frac{1}{2}(10)(10)\textrm{sin}(60)=25\sqrt{3}=43.3\ \mathrm{units}[/tex]

Review the graph of complex number z. What is the conjugate of z?
7 – 6i
6 – 7i
–7 + 6i
–6 + 7i

Answers

Answer: B. 6 - 7i

Step-by-step explanation:

The complex conjugate of the given graph of the complex number is 6-7i.

We have given that,

7 – 6i

6 – 7i

–7 + 6i

–6 + 7i

We have to determine the conjugate of z.

What is the conjugate of complex numbers?

changing the sign of the imaginary part of the complex number. To find the complex conjugate of 4+7i we change the sign of the imaginary part. Thus the complex conjugate of 4+7i is 4 - 7i.

Therefore the complex conjugate of the given graph of the complex number is 6-7i.

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Frank has 6 red socks, 8 black socks, and 10 white socks in his sock drawer. If Frank blindly reaches into his sock drawer, what is the probability that he will select a white sock and then another white sock? Round to the nearest percent A. 9% B. 16% C. 41% D. 80%​

Answers

Answer:

B

Step-by-step explanation:

The first probability is 10/24, and the second is 9/23. If you multiply these two fractoins you get 15/92. 15/92 is approximately equal to 16%.

Please help question in the picture

Answers

Answer:

64 m²

Step-by-step explanation:

Area of the trapezoid = ½(a + b)h

Where,

a = 6 m

b = 10 m

h = 8 m

Plug in the values

Area = ½(6 + 10)*8

Area = ½(16)*8

Area = 8*8

Area = 64 m²

Please help ASP!!!! A= positive, B=Negative, C=Zero​

Answers

Answer:

B. Negative

Step-by-step explanation:

So first, we want to locate the variable.

y (x/y) = (y/1) (x/y)

           = (xy/y)

           = x

The y/y cancels out and now we know we need to find the sign of x. Because x is to the left of 0, it's negative. Anything to the left decreases and anything to the left of 0 is (-).

You invest $17,804 in a CD that has a 6.275% annual interest rate, compounded continuously. How much will you have in 25 years?Round to the nearest cent.

Answers

Answer:

R = 3.813% per year.

Step-by-step explanation:

A = Accrued amount (principal + interest) P = Principal amount r = Annual nominal interest rate as a decimal R = Annual nominal interest rate as a percent r = R/100 n = number of compounding periods per unit of time t = time in decimal years; e.g., 6 months is calculated as 0.5 years. Divide your partial year number of months by 12 to get the decimal years. I = Interest amount ln = natural logarithm.

help me plz.................

Answers

Answer:

[tex]\frac{1}{8}[/tex] cup

Step-by-step explanation:

[tex]y=\frac{7}{8} -\frac{1}{4}-\frac{1}{2}[/tex]

[tex]y=\frac{7}{8}-\frac{2}{8}-\frac{4}{8}[/tex]

[tex]y=\frac{7}{8}-\frac{6}{8}[/tex]

[tex]y=\frac{1}{8}[/tex]

1.4
2
Lawrence wants to drive from Durban to Johannesburg 550 km. if he travels at
an average speed of 100 km/hr, how long does he tale to get there?
If he leaves at 08:42 what time will he arrive at his destination
1.5
2

Answers

Answer:

5 hr 30 minutes

2:12 pm

Step-by-step explanation:

s= 550km

v = 100km/hr

t = ?

SPEED = DISTANCE/ TIME TAKEN

or, v = s/t

or, 100km/hr = 550km/ t

or, t = 550/100

t = 5.5

t = 5 hrs 30 minutes

8:42

+5:30

13 :72

which is 14 :12 = 2 :12

Elijah's uncle gave him $300 to spend on baseball equipment. He bought a pair of cleats for $69.99, two baseball jerseys for $32.99 each, a new glove for
$79.99 and two pair of socks for $6.99 each. Without including tax, to the nearest dollar, how much money did Elijah have left?

Answers

9514 1404 393

Answer:

  $70

Step-by-step explanation:

The amount Elijah has remaining is ...

  $300 -(70 +2×33 +80 +2×7) = $300 -(70 +80 +2(33 +7)) = $300 -230 = $70

To the nearest dollar, Elijah has $70 left.

_____

Each amount is within a penny of the nearest dollar, so we can simply use the nearest dollar amounts for the prices. In order for the answer to be different, Elijah would have to purchase 50 or more items with this pricing (something.99).

Mary is having her living room and bedroom painted. Interior Designs USA charges $60.00 to evaluate the space plus $35.00 per hour of labor. Splash of Color charges $55.00 per hour with no initial fee. Which of the following are true? Select all that apply.

A) If it takes 7 hours to paint the two rooms, Interior Designs USA will charge the least.
B) Splash of Color will always charge the least.
C) If it takes more than 5 hours to paint the rooms, Splash of Color will be more cost effective.
D) If it takes 10 hours to paint the rooms, Splash of Color will charge $200 more than Interior Designs USA.
E) If it takes 3 hours to paint the rooms, both companies will charge the same amount.

Answers

Answer:

A and E

Step-by-step explanation:

A) 7 hrs in IDU will cost you $305.00 while SC cost $385

B) 4hrs in and SC will charge you more than IDU by $20

C) SC charges you more than IDU by $50 so IDU is more cost effective

D)SC will charge you $140 more than IDU but not $200

E) 55 x 3 = 165 while 35 × 3 105 plus 60 is 165 therefore it is the same

Determine the margin of error for a 90% confidence interval to estimate the population mean when s = 40 for the sample sizes below.
a) n=14
b) n = 28
c) n = 45
a) The margin of error for a 90% confidence interval when n = 14 is
(Round to two decimal places as needed.)
b) The margin of error for a 90% confidence interval when n=28 is
(Round to two decimal places as needed.)
c) The margin of error for a 90% confidence interval when n = 45 is
(Round to two decimal places as needed.)

Answers

Answer:

a) The margin of error for a 90% confidence interval when n = 14 is 18.93.

b) The margin of error for a 90% confidence interval when n=28 is 12.88.

c) The margin of error for a 90% confidence interval when n = 45 is 10.02.

Step-by-step explanation:

The t-distribution is used to solve this question:

a) n = 14

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 = 14 - 1 = 13

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 13 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 1.7709

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 1.7709\frac{40}{\sqrt{14}} = 18.93[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The margin of error for a 90% confidence interval when n = 14 is 18.93.

b) n = 28

27 df, T = 1.7033

[tex]M = T\frac{s}{\sqrt{n}} = 1.7033\frac{40}{\sqrt{28}} = 12.88[/tex]

The margin of error for a 90% confidence interval when n=28 is 12.88.

c) The margin of error for a 90% confidence interval when n = 45 is

44 df, T = 1.6802

[tex]M = T\frac{s}{\sqrt{n}} = 1.6802\frac{40}{\sqrt{45}} = 10.02[/tex]

The margin of error for a 90% confidence interval when n = 45 is 10.02.

please help me someone i really need this to get my grade up :(

Answers

Answer: D

2 1/2 divided by 1/4 = 10

hope this gets ur grade up keep trying ur best!! :D

7. Mrs. Paulson is constructing a 90% confidence interval for the difference of means based on independent
simple random samples from two populations. The sample sizes are n, = 6 and n, =14. She draws dotplots
of the sample data to check one of the conditions for using two-sample i procedures. Which of the following
descriptions of those dotplots would suggest that it is safe to perform inference?
(a) Both dotplots are roughly symmetric. There are no outliers in either dotplot.
(b) Both dotplots are roughly symmetric. The dotplot of sample 2 has an outlier.
(c) Both dotplots are strongly skewed to the right. There are no outliers in either dotplot.
(d) Both dotplots are roughly symmetric. Both dotplots have one upper outlier
(e) i procedures are not recommended in any of these cases.

Answers

The description that will show that it is safe to perform inference is that (a) Both dotplots are roughly symmetric. There are no outliers in either dotplot.

What description would make it possible to make inferences?

In order to use the two-sample t procedure to make inferences, certain conditions need to be met such as the sample being random and independent.

The variances for the groups in the data need to be equal which is why the presence of no outliers in either dotplot would present an safe opportunity to be able to perform inferences on the data.

In conclusion, option A is correct.

Find out more on two-sample t-tests at https://brainly.com/question/17438355.

the sum of 8 and joses score is 35 use the variable j yo represent josés score​

Answers

Answer:

8 + j = 35

subtract 8 from both sides

j = 27

Step-by-step explanation:

What is the solution to this equation?
In(2x + 4) = ln(x + 3)

Answers

x= -1 !! hope this helps

The solution to this equation, [tex]ln(2x + 4) = ln(x + 3)[/tex] is  [tex]x=(-1)[/tex] .

What is log ?

A logarithm is the power to which a number must be raised in order to get some other number .

We have,

[tex]ln(2x + 4) = ln(x + 3)[/tex]

Now, apply log rules

As we have [tex](ln)[/tex] on both which will be cancel out,

    [tex]2x+4=x+3[/tex]

    [tex]3x=3-4[/tex]

    [tex]x=(-1)[/tex]

So, on getting solution to the given equation we get the value of [tex]x=(-1)[/tex] .

Hence, we can say that the solution to this equation, [tex]ln(2x + 4) = ln(x + 3)[/tex]  is  [tex]x=(-1)[/tex] .

To know more about log click here

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What is
1. (1-1/4) x 4
2. 2- 1/4 x4 +4
3. 8 + 10 x 1/2

Answers

Answer:

1. 3

2. 5

3. 13

Step-by-step explanation:

there is your answers :)

Unit 10 circles homework 2 back side

Answers

There’s no question?

Find the common difference of the arithmetic sequence -2, -4, -6, ...

Answers

Answer:

-8

in this the arthmatic difference is table of 2

Answer:

the common d/f is that -2>-4>-6

Traci has 8 yards of fabric. She uses 10 feet of this fabric to make pillows. How much fabric does Traci have left

Answers

Answer:

She has 14 feet left

Step-by-step explanation:

1 yard = 3 feet of fabric

8 yards x 3 feet/yard = 24 feet

24 - 10 = 14 feet

Solve. Write or draw to explain. Amy has 12 stickers. Jen has 9 stickers. They place 7 stickers on each page of a book. How many pages are in the book? Math Spot thpicks​

Answers

Answer:

There's 3 pages in the book

Step-by-step explanation:

You add both of the amounts of stickers (12+9=21), then you divide by the amount on each page (21÷7=3)

Hope this helped!

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.

Answers

Answer: Jessica can use her measuring cup 11 times.

(hope this helps!)

If X = 12 inches, Y = 16 inches, and Z = 20 inches, what is the tangent of

Answers

Answer:

who do pow en odd an odd an 9 all 9 FM

Can someone help me with these two questions

Answers

the answer your looking for is C.

Cynthia says that when you evaluate the expression (21 3/4 + 4 1/2) - 5 3/12 you get a whole number. What whole number do you get?

Answers

Answer: 21

Step-by-step explanation:

First, convert the mixed fractions to improper fractions.

(87/4 + 9/2) - 21/4

Next, calculate within the parentheses:

87/4 + 9/2

Next, change the denominator of 9/2 to 4. To do that, multiply the denominator of 9/2 to get 4 to match the denominator of the first fraction. 9/2 * 2/2 = 18/4.

87/4 + 18/4 = 105/4

Then, 105/4 - 21/4 = 84/4

Finally, divide 84 by 4 and you get 21.

Please help please help please help

Answers

It should be 986m

4(17x6)= 408
2(17x17)= 578

408+578=986

Help please!!
Brainliest if right

Answers

Answer:

top and bottom

Step-by-step explanation:

x
What are the perimeter and area
of a square with side length of 12 in.?
A. P= 24 in., A = 24 in.?
B. P= 144 in., A = 48 in.2
O
C. P = 24 in., A = 144 in.2
O
D. P= 48 in., A = 144 in.2

Answers

Answer: P = 48 in, A = 144 in.2

Step-by-step explanation: Since a square has equal sides and we know one side length is 12 inches, then all the sides are 12 inches. For perimeter, we add all sides, which would equal 48 and for area, we multiply 2 of the sides, which would be 144.

HELPPP!!! i need to know this asap!!

Answers

Answer:

The first option

(-10, -7)

Step-by-step explanation:

Also I really like your pfp <33

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