A city councilwoman is concerned that the new contractor she hired is taking too long to replace defective streetlights. She would like to perform a hypothesis test to determine if the replacement time for streetlights under the new contractor is in fact longer than the replacement time under the previous contractor, which was 3.2 days on average. She selects a random sample of 12 streetlight service calls and obtains the following times to replacement (in days). Use a significance level of 0.05

6.2 7.15.4 5.57.52.6 4.3 2.9 3.7 0.7 5.6 1.7

Required:
a. Define μ in the context of the problem and state the appropriate hypotheses.
b. State and check the conditions for a hypothesis test of the mean. Since the sample size is smaller than 30, you will need to calculate a normal probability plot to determine if the data come from a normal distribution.

Answers

Answer 1

Answer:

There is significant evidence to conclude that the replacement time for streetlights under the new contractor is longer than the replacement time under the previous contractor.

Step-by-step explanation:

Given the data :

6.2 7.1 5.4 5.5 7.5 2.6 4.3 2.9 3.7 0.7 5.6 1.7

The hypothesis:

H0: μ = 3.2

H1 : μ > 3.2

n = sample size = 12

The sample mean, xbar = ΣX / n

xbar = 53.2 / 12

xbar = 4.43

Using calculator;

Sample standard deviation, s = 2.147

The test statistic :

(xbar - μ) ÷ (s/sqrt(n))

(4.43 - 3.2) ÷ (2.147/sqrt(12)

1.23 / 0.6197855

Test statistic = 1.985

The Pvalue using the Pvalue from Tscore calculator :

Tscore = 1.985 ; df = 12 - 1 = 11

Pvalue = 0.036

Since Pvalue < α ; We reject the Null

Hence, we conclude that the replacement time for streetlights under the new contractor is longer than the replacement time under the previous contractor.


Related Questions

Mr. Lopez was taking a drive to the mountains with his family they arrived at the mountains at 3:09 PM if the drive was two hours and 36 minutes long what time do Mr. Lopez family leave 

Answers

Answer:

they left at 12:34

Step-by-step explanation:

I did the math

9514 1404 393

Answer:

  12:33 pm

Step-by-step explanation:

Often, problems involving addition and subtraction of time values are best worked in 24-hour "military" time.

Here, we want to know the time that is 2:36 before 3:09 pm. We can write 3:09 pm as 15:09. Then the difference is ...

  starting time + travel time = ending time

  starting time = ending time - travel time

  starting time = 15:09 -2:36 = (15-2):(09-36) = 13:(-27) = 12:33

Mr Lopez's family left at 12:33 PM.

__

There are 60 minutes in an hour. 60-27=33.

The sides of a triangle have lengths 6, 8, and 11. What is
the length of the longest side of a similar triangle whose
perimeter is 75?

Answers

Answer:

48 is the answer

Step-by-step explanation:

The longest side of the similar triangle whose perimeter is 75 is 33 units.

What is a triangle?

A triangle is a geometric figure with three edges, three angles and three vertices. It is a basic figure in geometry.

The sum of the angles of a triangle is always 180°

The sides of the given triangle are,

6 units, 8 units and 11 units.

Also given that,

There is a similar triangle whose perimeter is 75 units.

To find the longest side of the similar triangle,

Let the sides of the similar triangle are 6x, 8x and 11x

The perimeter of triangle = 75

Implies that,

6x + 8x + 11x = 75

25 x = 75

x = 3

Since, the longest side of the similar triangle = 11 x

Substitute x = 3 here,

Longest side = 11 × 3 = 33 units

The required side of similar triangle is 33 units.

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Meiling and Jackie are playing a game of chance with a six-sided number cube. The sides of the cube are numbered 1 to 6. Meiling scores a point each time she rolls a number greater than 4.​


Answers

Answer:

D. Jackie rolls a number that is less than 3.

Step-by-step explanation:

Every time Meiling rolls a number greater than a four, she will get a point. This gives her two numbers that she can get a point off of, 5 and 6. So If Jackie were to roll a number less than a three, Jackie would also get two numbers that she can get a point off of, 1 and 2. So the answer "Jackie rolls a number that is less than 3" will give Jackie an equally likely chance for a point.

32
Select the correct answer.
Two friends are sitting on a seesaw at the park. The height, h(t), of the left seat, in inches above the ground, is modeled by a sine function. Lett
represent the time, in seconds, since the friends started seesawing.
t
0
1
2.
3
4
5
6.
ht)
24
48
24
0
24
48
24
If the friends start seesawing with the plank in a level position, how long does it take for the friend in the left seat to move upward, downward,
and then back to the initial position?

Answers

Answer:

I believe it would be 4 seconds

Step-by-step explanation:

PLATO/Edmentum

The time it takes for the friend in the left seat to move upward, downward, and then back to the initial position is 4 seconds.

What is a Function?

A function assigns the value of each element of one set to the other specific element of another set.

Two friends are sitting on a seesaw at the park. The height, h(t), of the left seat, in inches above the ground, is modeled by a sine function.

Let t represent the time, in seconds, since the friends started seesawing.

t       0    1    2  3  4   5   6h(t)  24 48 24 0 24 48 24

The friends start seesawing with the plank in a level position. The initial position at 0 of them is at 24.

The group has to come back to this position after moving upward and downward. The time it takes to reach upward is,

[tex]f(48)=t_{up}\\f(48)=1[/tex]

The time it takes to reach downward after going upward is,

[tex]f(0)=t_{down}\\f(0)=3[/tex]

Coming back to initial potion,

[tex]f(24)=t_{i}\\f(24)=4[/tex]

Thus, the time it takes for the friend in the left seat to move upward, downward, and then back to the initial position is 4 seconds.

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If m∠A = (11x + 37)° and x = 13, find m∠A and classify the angle (acute, right, obtuse, straight). Someone give me the two answers for this problem.

Answers

9514 1404 393

Answer:

  obtuse, straight

Step-by-step explanation:

If you insist on two answers, there is only one pair of answers that are self-consistent:

  obtuse, straight

__

m∠A = (11(13) +37)° = (143 +37)° = 180° . . . . a straight angle, also obtuse

What is the volume, in cubic meters, of a rectangular prism with a height of 14 meters, a width of 17 meters, and a length of 13 meters?

Answers

Answer: 3084

Step-by-step explanation: 14•17=238 238•13=3084

Answer:

3094

Step-by-step explanation:

l=13   w=17   h=14

v = L W H

V= ( 13 ) ( 17 ) ( 14 )

V= 3094 meters 3

 Your Solution:

                       V= 3094

Please help, I’m confused

Answers

Answer:

220/221

Step-by-step explanation:

cos math

What is the present value for $12,484 at 8% for two years

Answers

Answer:

Total = Principal * (1 + rate)^2

Total = 12,484 * (1.08)^2

Total = 14,561.34

Source http://www.1728.org/compint.htm

Step-by-step explanation:

my noluv.joel15 who wanna follow

Answers

I will follow you later

A park is in the shape of an isosceles triangle with a base of 56 feet. The perimeter of the park is 190 feet. How long is each of the equal sides of the park?

Answers

9514 1404 393

Answer:

  67 feet

Step-by-step explanation:

The perimeter is the sum of the base length and the two equal sides (s).

  190 = 56 +2s

  134 = 2s . . . . . . subtract 56

  67 = s . . . . . . . . divide by 2

Each of the equal sides is 67 feet long.

There are 30 marbles in a bag. There are 10 red marbles, 7 green, 6 blue, and 7 yellow. If you randomly grab a single marble, what are the odds of grabbing a yellow?

Answers

Answer:

Step-by-step explanation:

The odds of grabbing a yellow marble from the bag are 7/30 or 0.233.

What is Probability?

It is a branch of mathematics that deals with the occurrence of a random event.

The odds of grabbing a yellow marble can be find by dividing the number of yellow marbles by the total number of marbles in the bag:

Odds of grabbing a yellow marble = Number of yellow marbles / Total number of marbles

By given there are 7 yellow marbles and a total of 30 marbles in the bag, so:

Odds of grabbing a yellow marble = 7 / 30.

Therefore, the odds of grabbing a yellow marble from the bag are 7/30 or approximately 0.233 or 23.3%.

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9. The ages of A and B are in the ratio 3:5. Four years later,
the sum of their ages is 48. Find their present age

Answers

Answer:

A = 15  B = 25       in four years  19+29 = 48

Step-by-step explanation:

age A and B ratio is 3 to 5

A+4 + B+4 = 48

    A + B  = 40

    A/B = 3/5     A = 3B/5

    A + B  = 40

 3B/5 + B  = 40

   3B  + 5B = 200          multiple both sides by 5

       8B  = 200

         B  =  25

         A  = 3B/5

         A  = 3(25)/5

         A  = 15

Answer:

15

Step-by-step explanation:

answer and show Actual PROOF and ill give brainliest

Answers

Answer:

105m^3

Step-by-step explanation:

The volume of a rectangular prism is calculated by multiplying l*w*h. Basically, just multiply all the numbers together.

So that would be 3*5*7

Bob and Venessa share $52. if Bob gets three times what Venessa gets, how much does he get?​

Answers


Answer is 39

Venessa- x
Bob- 3x
3x+x=52
4x=52
x=13 (Venessa)
3x=3*13=39 $ (Bob)

If ∠C and ∠D are complementary angles, m∠C = (4x + 3)°, find m∠D = (15x - 8)°, find m∠D.

Answers

Answer:

67

Step-by-step explanation:

4x+3+15x-8=90(complementary angle)

x=5

now D = 15*5-8

d=67

What is 57 divided by 90?

Answers

Answer:

0.63 should be your answer

Answer;

0.6333333

Step-by-step explanation:

I think it's helps you

5,000 is invested at an interest rate of 8% compounded annually. how much is the investment return after 20 years?​

Answers

Step-by-step explanation:

5k×8×20

_______ =800

100

Answer:

≈ 23305

Step-by-step explanation:

The amount A is calculated as

A = P [tex](1+r)^{t}[/tex]

P is the principal

r is the interest rate

t is the time in years

A = 5000 [tex](1+0.08)^{20}[/tex]

   = 5000 [tex](1.08)^{20}[/tex]

   ≈ 23305 ( to the nearest whole number )

which is greater 0.98 or 0.980​

Answers

Answer:

They are equal.

Step-by-step explanation:

Answer:

both are equal its just a zero added

A cubical tank of edge 12 cm is half filled with water. The water is poured into an empty rectangular tank measuring 10 cm by 8 cm by 7 cm until it is full. How much water is left in the cubical tank? Give your answer in millilitres.

Answers

Answer:

3040000mm³

Step-by-step explanation:

Volume of a cube = a³ ; a = size of edge

Volume of cubical tank = 12³ = 12 * 12 * 12 = 1728 cm³

Half filled cube = 1728 / 2 = 864 cm³

Volume is f rectangular tank :

V = length * width * height

V = 10 * 8 * 7 = 560 cm³

Volume of water left in cubical tank :

(864 - 560) = 304cm³

1cm³ = 1000mm³

304cm³ = 304 * 1000 = 3040000mm³

Please help me with this ASAP ASAP please please help

Answers

Answer:

Step-by-step explanation:

Base perimeter: 4 x 2 x π = 8π

LA = 8π x 6 = 48π

Base area = 4^2π = 16π

SA = 16π x 2 + 48π = 80π

V= 16π x 6 = 96π

-9/5+-2/3+1/5+3/5 please solve someone

Answers

Answer:

-5/3

Step-by-step explanation:

-9/5 + -2/3 + 1/5 + 3/5

= (-9/5 + 1/5 +3/5) - 2/3 (combine the like terms)

= -1 - 2/3

= -5/3

A bag contains 8 red marbles and 4 blue marbles. You randomly pick a marble and then pick a second marble without returning the first marble to the bag. What is the probability that both marbles are red?

Answers

Answer:

0.50%

Step-by-step explanation:

Given vectors A=(1i+7j−2k)N and B=(−1i−10j+13k)N, find the magnitude of resultant of these two vectors and angle that the resultant of these two vector makes with the z axis.
IRI= ____ N,
γ=_____ °. pls help mangota​

Answers

Answer:

Step-by-step explanation:

y= 7.2

Iri=21.1

Answer:

that should be correct:)

Step-by-step explanation:

y= 7.2

Iri=21.1

10. Find the measure of angle x.
11. Find the measure of angle ?

Answers

9514 1404 393

Answer:

  10. 28°

  11. 65°

Step-by-step explanation:

10. The two angles are complementary, so the unknown angle is ...

  x = 90° -62° = 28°

__

11. The three angles total 180°, so the unknown angle is ...

  ? = 180° -55° -60° = 65°

Brainliest for correct answer asap

Answers

Answer:

its the first one. Times the bigger numbers and add the indices. so it 16^7

Answer: A 16(7)

Step-by-step explanation:

First you multiply your base numbers,[4x4] to get 16 then you add your exponents [2+5] to get 7 and remember you can only add exponents not multiply them.

Seven cards are drawn from an ordinary deck. In how many ways is it possible to draw ​(b) only 8​'s, ​'s and ​(c) no ​'s, ​'s and ​(d) exactly 2 or ​; ​(e) spades and ​hearts? ​(a) Number of ways to draw only ​'s ​= 0 ​(b) Number of ways to draw only ​'s, ​'s, and ​'s ​= 924 ​(c) Number of ways to draw no ​'s, ​'s, and ​'s ​= 3838380 ​(d) Number of ways to draw exactly 2 s or s ​= 3,801,028 ​(e) Number of ways to draw spades and hearts​ = 55770 Question is complete. Tap on the red indicators to see incorrect answers.

Answers

Complete question :

Seven cards are drawn from an ordinary deck. In how mnat ways is it possible to draw (a) only 5s (b)only 8s, 9s, and 10s, (c) no 8s, 9s, and 10s (d) exactly 2 jacks or kings, (e) 5 spades and 2 hearts?

Answer:

0; 792 ; 100396 ; 30408224 ; 18643560 ;

Step-by-step explanation:

Number of cards in a deck = 52

Number of cards to be drawn = 7

Using combination:

nCr = n! ÷ (n-r)!r!

A.)

Number of 5's in a deck = 4

4C7 = 0

(B.)

only 8s, 9s, and 10s,

Number of 8, 9 and 10's = 4 *3 = 12

12C7 = 12! ÷ 5!7! = 792

(C)

no 8s, 9s, and 10s ;

Number of cards to select from = 52 - (3(4)) = 40C7 = 18643560

(D)

exactly 2 jacks or kings,

Number of jack or king in deck = 8 ; other 5 could be any of the rest : (52 - 8) = 44

8C2 * 44C5 = 28 * 1086008 = 30408224

(e) 5 spades and 2 hearts?

Number of spades = 13

Number of hearts = 13

13C5 * 13C2

1287 * 78 = 100396

A stack of books is 35 inches high. If each book is 1 3/4 inches thick, how many books are in the stack?

Answers

Answer:

20 books

Step-by-step explanation:

Height of stack = 35 inches

Thickness of one book [tex] =1\frac{3}{4} =\frac{7}{4}\: in [/tex]

No. of books

[tex] = 35 \div \frac{7}{4} \\ \\ = 35 \times \frac{4}{7} \\ \\ = 5 \times 4 \\ \\ = 20[/tex]

1. 4 less than q
2. The product of 5 and x, reduced by 3
Guys please help me I need this note to pass 6th grade

Answers

1. Q-4
2. 5x-3
Hshdjdjdjsjdjjdndjdjdjdjjd

simplify 8x+7-x-4


help meeeeee!!!​

Answers

Answer:

7x + 3

Step-by-step explanation:

Let's simplify step-by-step.

8x + 7 − x − 4

= 8x + 7 + −x + −4

Combine Like Terms:

= 8x + 7 + −x + −4

= (8x + −x) + (7 + −4)

= 7x + 3

Answer:

= 7x + 3

hope this helps and is right. p.s i really need brainliest :)

if my answer is wrong then I am incredibly sorry!

What is the correct answer for this question?

Answers

Answer:

3 2/3 inches (the last one)

Answer:

[tex]maybe \: letter \: a[/tex]

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