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

Which expression is equivalent to xy^2/9?

Answers

9514 1404 393

Answer:

  the correct answer is marked

Step-by-step explanation:

The denominator of a fractional exponent becomes the index of the radical when the power is written using a radical. The fractional power only applies to the y-factor, so that is all that is under the radical.

  [tex]\displaystyle xy^{\frac{2}{9}}=x\cdot (y^2)^{\frac{1}{9}}=\boxed{x\sqrt[9]{y^2}}[/tex]

A country's population in 1990 was 156 million. In 1996 it was 162 million. Estimate the population in 2016 using the exponential growth formula. Round your answer to the nearest million. P = Aekt Enter the correct answer.​

Answers

Answer:

184

Step-by-step explanation:

determine if the work for each problem is correct correct only errors and explain your thinking ​

Answers

Answer:

v= BH

the second part is wrong the base is 7.5 not 9.5

so the base look like this

v = 7.5(13)

v = 97.5

Step-by-step explanation:

BRAINLIEST FOR CORRECT ANSWER, IM FAILING SCHOOL AND NEED HELP ASAP. EVEN OFFICIAL HELP COUNTS

Answers

they are vertical angles!!

Answer:

Verifal angles I think but I'm not necessarily sure!!!

There is a 30% probability of
hail. What is the probability
that it will NOT hail?

Answers

Since we’re taking from a whole of 100% every time, we just subtract the 30 from 100 and get 70%

Answer:

70% probability

Step-by-step explanation:

  100% probability

 -30% probability

 =70% probability

depressed ppl say here

Answers

here

hehbsheheuehebdbd

Answer:

lol are you depressed ..........

A CD has a diamter of 4.75 inches, Find the circumference, Use calculator pi or 3.14. Round to the nearest hundredth, if necessary.

WILL GIVE BRAINLIEST!!!

Answers

Answer:

15 in.

Step-by-step explanation:

What is the median value of the data set shown on the line plot?

Enter your answer in the box.

[_]

Answers

Answer:

6 is the median...

Step-by-step explanation:

Well first off, you need to know what a median is.

Let's break down the root/suffix/prefix.

Med= Meduim/middle

Median means the middle value.

Let's look at our data:

Skip zero

1-1- First

2-1- second

3-2-third

4-2-forth

5-3 fifth

6-4 - Six is in the middle of the line, making it the median.

7-3 seventh

8-3 eighth

9-2 ninth

10- 0 tenth

11-1 eleventh

12-0 twelfth

What's in between 1-12?  6!!! There's our answer!!!

I hope this helped you! Have a great day!!!

solve for the missing side and round to the nearest tenths place

Answers

Answer:

A. 22.5

Step-by-step explanation:

Apply Trigonometric function.

Reference angle = 64°

Opposite side to 64° = x

Hypotenuse = 25

Apply SOH:

Sin 64 = Opp/Hyp

Sin 64 = x/25

25 × Sin 64 = x

22.4698512 = x

x = 22.5 (nearest tenth)

Graph the polynomial function,
f(x) = – x3 + 2x2

Answers

See attatched picture

What’s the volume of the rectangular prism of 2cm, 7/3 cm and 2cm?

Answers

Answer:

9 1/3 cm³

Step-by-step explanation:

First multiply two numbers.

2x2=4

Then multiply the product by the third number.

4x7/3

4  x   7

1   x   3

= 28/3 or 9 1/3

--

hope it helps

Mensualmente el número de árboles talados aumenta en un 9% respecto del mes anterior. Si este mes hay 85.000 árboles talados, ¿cuántos árboles talados habrá, aproximadamente, en 6 meses más?

Answers

Answer:

FV= 639.483 arboles

Step-by-step explanation:

Dada la siguiente información:

Cantidad de árboles talados (A)= 85.000

Proporción de crecimiento (g)= 9% mensual

Cantidad de meses (n)= 6

Para calcular el total de árboles talados en 6 meses, tenemos que usar la siguiente formula:

FV= {A*[(1+i)^n - 1]} / i

A= cantidad de árboles talados

i= proporcion de crecimiento

n= cantidad de  meses

FV= {85.000*[(1.09^6) - 1]} / 0.09

FV= 639.483 arboles

Ahora, la cantidad de árboles que se talaran en el sexto mes:

FV= PV*(1+i)^n

FV= 85,000*(1.09^6)

FV= 142.553

The cost of one pen when pens are priced at 5 for p dollars

I really need help on this

Answers

5 dollar for one pen

Answer:

$1

Step-by-step explanation:

If 5 pens = $p, then 1 pen = $p/5.

But because 5 pens = $p, it would be the same thing as 5 = p because you just take off the labels.

So p = 5 and one pen would be:

$p/5 = 1

5/5 = 1

1 = 1

I can't figure this problem out Please, I need some help.​

Answers

Answer:

66

Step-by-step explanation:

5. Find the surface area of a sphere with
the radius of 1.5 cm.
a. 28.26 cm
b. 7.065 cm
c. 18.84 cm
d. 14.13 cm

Answers

it should be A) 28.26cm

I NEED HELP ASAP PLEASEEEE!!!!! Given the cube, what is the total surface area and volume?

Answers

Answer:

864

Step-by-step explanation:

144x6

Answer:

b

Step-by-step explanation:

Marie spent $15 on 4 identical jars of jelly. Each jar of jelly costs the same amount. How much did 1 jar of jelly cost? Use paper to show your work.
One jar of jelly costs $

Answers

Answer: $3.75

Step-by-step explanation:

First you would have to find the unit rate.

$15 / 4 jars of jelly = $3.75

Therefore, 1 jar of jelly = $3.75

Answer:

the answer is $3.75

Step-by-step explanation:

15 ÷ 4= 3.75

to verify your answer multiply

3.75 × 4= 15

Will give Brainly

Find the probability that a
randomly
selected point within the circle falls
in the red shaded area.
60°
60°
r= 4 cm
[? ]%
Round to the nearest tenth of a percent.

Answers

Answer: 33.3%

s Step-by-step explanation: The combined arc length of the red area is 120, which is 1/3 of 360, the full arc. So the probability is 1/3, or 33.3%. Hope this helps!

The probability that a randomly selected point within the circle falls

in the red shaded area will be 33.33%.

What is probability?

Probability is defined as the ratio of the number of favorable outcomes to the total number of outcomes in other words the probability is the number that shows the happening of the event.

Probability = Number of favorable outcomes / Number of sample

Given that the shaded red sector has an angle of 60 degrees and the radius of the circle is 4 cm. The probability will be calculated as:-

The formula for a circle's sector's area is (Ф/360°) x π(r²), where r is the circle's radius and is the sector's angle.

Area of shaded region =  (Ф/360°) x π(r²),

Area of shaded region = ( 60 / 360 ) x π (4²)

Area of shaded region = 8.377 square cm

Total shaded area = 2 x 8. 377 = 16.75 square cm

Total area of circle = π (4²) = 50.265 square cm

The probability is calculated by the formula below:-

Probability = Number of favorable outcomes / Number of sample

Number of favorable outcomes = 8.377

Number of sample = 50.265 square cm

Probability = 8.377 / 50.265 = 0.3333 = 33.33%

Therefore, the probability that a randomly selected point within the circle falls in the red-shaded area will be 33.33%.

To know more about probability follow

https://brainly.com/question/27930712

#SPJ5

PLEASE HELP ME WITH GEOMETRY :(

Answers

Answer:

1st option

Step-by-step explanation:

You have to take the radius and times it by 1 which gives you 8 in.

there are 6 rows of chairs 4 rows are empty

Answers

Answer:

then only 2 rows are full

Step-by-step explanation:

im confused but if thats it then thats the answer if im right mark me brainliest

:>

Please help me. There are 25 students in Mrs. Benatar‘s class at the beginning of the school year, and the average number of siblings for each student is three. A new student with eight siblings join the class in November. What is the new class average for number of siblings? Round your answer to the nearest hundredth.

Answers

Answer: 3.19

Step-by-step explanation:

So to find the average I used a simple but pretty effective method

3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+8/26=3.1923

So the new average is 3.19


What is the area of ADEF?

Answers

Answer:

6 sq ft

Step-by-step explanation:

The cheerleaders are making a banner that is 8 feet wide the length of the banner is 1 1/3 times the width of the banner how long is the banner

Answers

Answer:10 2/3 feet

Step-by-step explanation: 8 times 4/3= 32/3=10 2/3 feet

Good job people They are right

5. In a right triangle, the sum of the lengths of the two legs is 100 meters. What are the lengths of the three sides
of this right triangle if the triangle's area is maxed out?

Answers

Answer:

6m by 8m by 10m

Step-by-step explanation:

6²+8²= 100

36+64=100

100=100

1.give the sequence 8.5.2.-1,...at what term will the number become -25? A.11th term B.10th term C.12th term D.20th term 2.which of the following is an algebraic esprression? A.3+5 B.n-1-14 C.3+5=8 D.x=53 3.what is the sum of the first 5 even numbers? A.30 B.20 C.10 D.50

Answers

Answer: 1. C(12) 2. B(n-1-14) 3. A(30)

Step-by-step explanation: For number one the nth term with common difference d and first term a is a+(n-1)d=nth term, plug in the values you have and solve for n to get 12. For number 2 an algebraic expression has a variable and a constant but doesn't have an equal sign. So it is B. For number three just add them up. Hope this helped!  

Tom has 2 1/2 times as many cards as Harry. Together they have 98 cards. How many cards do they each have?

Answers

Answer:

Tom has 70 cards, and Harry has 28 cards.

Step-by-step explanation:

Let h = number of cards Harry has.

Then the number of cards Tom has is 2 1/2 * h = 2.5h.

Together they have 2.5h + h = 3.5h number of cards.

Together they have 98 cards.

3.5h = 98

h = 98/3.5

h = 28

Harry has 28 cards.

Tom has 2.5h = 2.5 * 28 = 70

Answer: Tom has 70 cards, and Harry has 28 cards.

Use inverse trigonometric functions to solve each problem.
A flag pole 30 feet tall casts a shadow of 50 feet on the ground. Find,
to the nearest tenth of a degree, the angle of elevation of the sun.
a.30°
b.31°
c.60°
d.61°

Answers

Answer:

BBBBBBBBBB

Step-by-step explanation:

2 Easy 7th Grade questions but its due in 7 min HELP ASAP
A cylinder-shaped beaker is 6 inches tall and its base measures 4 inches across. For a science experiment, Gloria must fill 1/3 of the beaker with water. How much water will Gloria use for the experiment?


What is the height of the cone if the volume is 12 pie ft ? And radius is 3ft

Answers

Answer:

Step-by-step explanation:

Problem One

V = pi r^2 h

V = 3.14 * (4/2)^2 * 6

V = 3.14 * 4 * 6

V = 75.36

However, that is not the answer. The answer is 1/3 of that amount.

V1 = 1/3 * 75.36

V1 = 25.12

Problem 2

V= `12 pi

r = 3 feet

Formula

V = 1/3 pi r^2 h

12* pi = 1/3 * pi * 3^2 * h      Cancel the pi s.

12 = 1/3 * 9 * h

12 = 3 h                                Divide by 3

12/3 = h

h = 4

A school district is considering moving the start of the school day at Groveland High from 8:00 a.m. to 9:00 a.m. to allow students to get more sleep at night. They want to estimate how many more hours of sleep teens get if their school starts at 9:00 a.m. compared to teens whose schools start at 8:00 a.m. The district takes random samples of 50 of students from Groveland High and 39 students from Phillips High School, which starts at 9:00 a.m., and surveys them about their sleep habits. The sample mean number of hours of sleep per student at Groveland is 7.1 hours, and the standard deviation is 1.7 hours. At Phillips, the sample mean is 8.3 hours of sleep, with a standard deviation of 1.9 hours. What is the 90% confidence interval for the difference in mean hours of sleep for students at the two high schools

Answers

Answer:

The answer is "[tex]\bold{(7.1-8.3) \pm 1.665 \sqrt{\frac{(1.7)^2}{50}+\frac{(1.9)^2}{39}} }\\\\[/tex]"

Step-by-step explanation:

Given values:

[tex]\bar{x_1}=7.1\\\\\bar{x_2}=8.3\\\\s_1=1.7\\\\s_2=1.9\\\\n_1=50\\\\n_2=39[/tex]

Using formula:

[tex]\to (\bar{x_1} -\bar{x_2}) \pm t \sqrt{\frac{(s_1)^2}{n_1}+\frac{(s_1)^2}{n_2}} \\\\[/tex]

Put the values in the above formula:

[tex]\to (7.1-8.3) \pm 1.665 \sqrt{\frac{(1.7)^2}{50}+\frac{(1.9)^2}{39}} \\\\[/tex]

A. Find the volume of a rectangular room measuring 22.75 ft. x 30 ft. x 14 ft.
B. Find the BTUs needed for that room if it faces South with poor insulation.


Help asap

Answers

Answer:

12 BTU

Step-by-step explanation:

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