A car rental company is interested in the amount of time its vehicles are out of operation for repair work. A random sample of 21 cars showed that, over the past year, the numbers of days that each of these cars had been inoperative were as follows: 15, 11, 19, 24, 6, 18, 20, 15, 18, 12, 14, 19, 5, 21, 12, 11, 8, 10, 7, 2, 14 Assuming that the population is normally distributed, construct a 95% confidence interval for the mean number of days that vehicles in the company's fleet are out of operation.

Answers

Answer 1

Answer:

(10.891; 15.869)

Step-by-step explanation:

Given the data::

15, 11, 19, 24, 6, 18, 20, 15, 18, 12, 14, 19, 5, 21, 12, 11, 8, 10, 7, 2, 14

The confidence interval is obtained using the relation :

Mean ± margin of error

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

Using a calculator, the mean value of the data and standard deviation above is :

Mean = Σx / n ; n = sample size

Mean, xbar = 281 / 21

Mean = 13.38

Standard deviation , s = sqrt[Σ(X - xbar)²/ n-1]

Standard deviation, s = 5.82

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

Zcritical at 95% confidence level = 1.96

Margin of Error = 1.96 * 5.82/sqrt(21) = 2.489

Confidence interval :

Mean ± margin of error

13.38 ± 2.489

Lower boundary = (13.38 - 2.489) = 10.891

Upper boundary = (13.38 + 2.489) = 15.869

(10.891; 15.869)


Related Questions

A family decides to put tiles in the entryway of their home. The entryway has an area of 7 square meters. If each tile is 5 centimeters by 5 centimeters, how many tiles will it take to cover the entryway?

It will take ______ tiles to cover the entryway.​

Answers

9514 1404 393

Answer:

  2800 tiles

Step-by-step explanation:

Each tile has an area of (0.05 m)² = 0.0025 m². Then the number of tiles required to cover 7 square meters is ...

  (7 m²)/(0.0025 m²/tile) = 2800 tiles

It will take 2800 tiles to cover the entryway.

at his last baseball game, George missed 35% of the pitches thrown at him. based on this information, how many pitches will he miss if he has 40 pitches thrown at him?

Answers

Answer:

14

Step-by-step explanation:

35% of 40

= 35/100 × 40

= (35×4)/10

= 140/10

= 14

Which of the following is not an exterior angle of triangle BHE

Answers

Answer:

I dont know

Step-by-step explanation:

PLEASE HELP BRAINLIEST.

Answers

Answer:

98 cm^2

Step-by-step explanation:

it contains 8 right triangles and one square;

the area of the square = 8 x 8 = 64

.

the area of all the traingles; 4 x 8 = 32

.

sum up; 32 + 64 = 98 cm^2

Select the correct answer.
What is the factored form of this expression?
X^2 - 12x + 36
OA. (x+6)^2
OB. (x - 12)(x - 3)
OC. (x-6)^2
OD. (x-6)(x+6)

Answers

Answer:

C

Step-by-step explanation:

since -6 and -6 are factors of 36 that add up to equal -12, the factored form of the expression is (x-6)^2.

The list below shows the different choices of pizza at the local pizza shop: Pepperoni: 11 Supreme: 7 Cheese: 6 Hawaiian: 3 Based on these results, what is the theoretical probability of choosing a Hawaiian Pizza?​

Answers

Step-by-step explanation:

11 + 7 + 6 + 3 = 27

total amount of pizza = 27

Hawaiian pizza = 3

3/27 = 1/9

x^2 +10x+21 factor this

Answers

Answer:

(x+3)(x+7)

Step-by-step explanation:

3 and 7 are factors of 21, and they add up to 10.

Find the simple interest
$154.40 for 4 years at 8 1/2%

Answers

Answer:

$52.50 (rounded)

Step-by-step explanation:

I = Prt

I = 154.4(.085)(4)

I = 52.496

An item on sale costs 85% of the original price. The original price was $33.
Use the ALEKS calculator to find the sale price.
?

Answers

Answer: 28.05

Step-by-step explanation:

Solve for x 103 (3x+4)

Answers

309x+412
X=309 over 412
X=3 over 4

Find the variance of the data. 22, 34, 7, 27, 25 x = 23 Variance (²) = [?]​

Answers

Therefore, the variance (²)  of the data. 22, 34, 7, 27, 25 x = 23  is 79.6.

Variance calculation

To find the  variance of a set of data, you can follow these steps.

Calculate the mean of the data set.

Mean = (22 + 34+ 7 +27 +25)= 23.

Substract the mean from each data point and square.

(22 -23)² =1

(34 -23)² =121

(7-23)² =256

(27-23)² =16

(25 -23)² =4

Find the mean of the squared differences.

The mean of squared differences = (1 + 121+ 256+ 16+ 4) /5 = 79.6

Therefore, the variance (²) is 79.6.

Learn more about variance below.

https://brainly.com/question/30125349

#SPJ1

A car is traveling at a speed of y miles per hour. which situation would be described by the expression 1.2y?

Answers

This expression means acceleration by 20%

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).

Between 2002 and 2012 the population of the town Astopia fell by 4%.

If the population in 2012 was 252,960 find the population of the town in 2002.

Answers

Answer:

https://studyandanswers.com/mathematics/question18362805#

Step-by-step explanation:

A company has recently been hiring new employees. Today the company has 26% more employees than it did a year ago. If there are currently 56,700 employees, how many employees did the company have a year ago?​

Answers

Answer:

I am pretty sure 237

Step-by-step explanation:

nabiha wants to decorate her home for an upcoming party she bought a roll of ribbon from "dollarama" which is 3.2 m long

(a) how many 15 cm of ribbon can be cut from a 3.2m long ribbon
(b) how long is the remaining peice

Answers

Answer:

A = 21

B = 5

Step-by-step explanation:

1 meter = 100 centimeters

This means that she has 320cm of ribbon. Now you need to divide 320 by 15

320/15 = 21.3333333333

So to check your work you could multiply 15 by 21

15 x 21 = 315

This answer is less than 320 so you now know that Nabiha can cut 21 pieces of ribbon that are 15cm long. You also know that the remaining piece is 320 - 315 = 5.

Please award me brainiest! Hope this helps!

Each side length is doubled. What is the AREA of the new figure?

Answers

Answer:

24 square units

Step-by-step explanation:

When the sides are doubled, new figure so obtained will have:

Base (b) = 2*3 = 6 units

Height (h) = 2*4 = 8 units

Area of the figure when each sides are doubled

[tex] = \frac{1}{2} \times b \times h \\ \\= \frac{1}{2} \times 6 \times 8 \\ \\ = 3 \times 8 \\ \\ = 24 \: square \: unite[/tex]

Amy buys 22 envelopes for 13p each and pays with a £5 note.
How much change does she get?
Give your answer in pounds, £.​

Answers

hi there lol have a great day

How to find rate of change on a table

Answers

Answer:

   __X__l__Y_

        1     l    3

        5    l    6

        9     l    9

        13   l    12

        17   l    15

        21   l    18

On the right side, the numbers get larger by adding three each time. On the left side, the numbers get larger by adding 4 each time. It would be the same for any other pair of numbers when you add 4 to the left, and 3 to the right. For instance, the next pair would be (25 , 21). 25 would be the X value, and 21 would be the Y value.

Help meeeeeeeeeeeeeeeee

Answers

Answer:

27

Step-by-step explanation:

The width of the frame is 9. If Marcia needs it to be THREE times as long as it is wide, that would mean she would have to multiply 3 x 9 which equals 27

HOW LONG IS PQ?
special right triangles khan academy

Answers

Answer:

Step-by-step explanation:

The side opposite to the angle 30 degree in right triangle is half of hypothenuse.

What's 2+2 ?

First one to answer gets cash prize!

Answers

Answer:

4

(if this is a joke then the answer's 5, a fish, etc...)

Answer:

4

Step-by-step explanation:

Pleaseeee helpppppppp

Which integer represents 4° below zero

A: 0
B:4
C: -4
D: -0

Answers

it is -4




explanation:when you get under zero you start going up the numbers regularly except they have the negetive sign

10th grade geometry question. I will give brainliest. NEED HELP ASAP

Answers

Answer:

(-4+5)-1

Step-by-step explanation:

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

For which color is the difference between the theorectical probability and experimental probability greatest? A. Brown; The experimental probability is 19.52%, and the theoretical probability is 25%. B. Orange; The experimental probability is 18.9%, and the theoretical probability is 15%. C. Yellow; The experimental probability is 16.96%, and the theoretical probability is 20%. D. Green; The experimental probability is 22.7%, and the theoretical probability is 15%.

Answers

Answer: green

Step-by-step explanation:

Solve 58 - 10x * 20 * 9x.
O A rs-2
B. X-2
C. XS2
O D. x22

Answers

The answer to your question might be B

y = –3x + 7
y = 2x – 8

Answers

Answer:

Step-by-step explanation:

Using the comparison, substitution, and elimination method, the answer is:(x,y)=(3,-2)

When rewriting the equation the answer is:

3x+y=7

2x-y=8

PLEASE HELP WILL MARK BRAINLIEST

Answers

Answer:

Part 1: f(x)=0 has 0 solutions

Part 2: g(x)=0 has 2 solutions

Part 3: h(x)=0 has 1 solution

I graphed them

The length of the rectangle is 9 cm.
The perimeter of the rectangle is 31 cm.
(b) Work out the width of the rectangle.

Answers

Answer:

Perimeter = 2(L+W)

31 =2(9+w)

31 =18+2W

31-18=2W

13=2W

W=13/2

W=6.5cm

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