1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
puteri [66]
2 years ago
10

A city councilwoman is concerned that the new contractor she hired is taking too long to replace defective streetlights. She wou

ld 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.
Mathematics
1 answer:
satela [25.4K]2 years ago
5 0

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.

You might be interested in
A slope of -5 that passes through (2,15)
amm1812

Answer:

y=-5x+25

That is the answe in slope intercept form

8 0
3 years ago
Question 1: Explain how the letter x (or any letter) is used when writing expressions, and give an example. How are expressions
BaLLatris [955]

Answer:

Question 1:

The letter x or any letter used when writing an expression is representative of  unit of an idea, quantity or measure, such that it can be translated in the expression to provide information about a related idea

Question 2:

The expression can be translated as two times the expression three (variable) x minus two (variable) y plus the constant 7

Question 3:

In the first expression, the like terms are;

10y and (-2y),

3x and x

In the second expression, the like terms are;

-y and -2y

3x and 4x

The first expression simplifies to 8y + 4x + 10

The second expression simplifies to  7x - 3y + 6

Question 4:

The expression is evaluated as 122

Question 5:

The equivalent expression of the expression 3(4x + 2y) + 5x, is 17x + 6y

To prove when x = 1 and y = 2 we have;

3(4×1 + 2×2) + 5×1 is 29

17×1 + 6×2 is 29 which are equivalent in value

Step-by-step explanation:

Question 1:

The letter x or any letter used when writing an expression is representative of  unit of an idea, quantity or measure, such that it can be translated in the expression to provide information about a related idea

Example;

If x is the symbol representing the average number of oranges sold in 1 hour, then the expression for the number of oranges sold per day of 24 hours  = 24·x

An expression is a written mathematical symbolic statement that shows the the finite merging together of representative symbols by the mathematical operations that govern the present constraints

An equation is a statement that two expressions are equal

Question 2:

The given expression is 2(3x - 2y) + 7

The parts are;

The coefficient of (3x - 2y) = 2

The constant term = 7

The variables are x and y

Which gives

The coefficient of the variable x = 6

The coefficient of the variable y = -4

The expression can be translated as two times the expression three (variable) x minus two (variable) y plus the constant 7

or

The expression can be translated as two times the bracket open three times (variable) x minus two times (variable) y bracket close plus the constant 7

or

The expression can be expanded as 2(3x - 2y) + 7 → 6·x - 4·y + 7 which is expressed verbally as follows;

Six times (variable) x minus four times (variable) y plus the constant 7

Question 3:

The expressions are;

10y + 3x + 10 + x  - 2y..........................(1)

3x - y + 4x + 6 - 2y,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,(2)

In the first expression, the like terms are;

10y and (-2y),

3x and x

In the second expression, the like terms are;

-y and -2y

3x and 4x

They are like terms because they can be simply added together to simplify the expressions as follows

10y + 3x + 10 + x  - 2y gives 10y - 2y + 3x + x  10  to give 8y + 4x + 10

Also

3x - y + 4x + 6 - 2y  gives  3x+ 4x - y  - 2y + 6 to give 7x - 3y + 6

Question 4:

The expression 8x² + 25·y when x = 3 and y = 2 is evaluated by replacing (putting) the value x and y (into the expression)

The expression is then evaluated as 8×3² + 25×2 which is the same as 72 + 50 or 122

Question 5:

To write the equivalent expression of the expression 3(4x + 2y) + 5x, we expand the expression as follows;

3×4x + 3×2y + 4x which is 12x + 6y + 4x

We combine like terms;

12x + 5x + 6y which is 17x + 6y

To prove we can check by substituting a value for each of the variables x and y such as x = 1 and y = 2

3(4×1 + 2×2) + 5×1 is 29

17×1 + 6×2 is 29

5 0
3 years ago
If g(x) = 4x^2 - 16 were shifted 7 units to the right and 3 down, what would the
Kitty [74]

Answer:

The new equation is h(x)=4(x-7)^2-19

Step-by-step explanation:

Given : Function g(x) = 4x^2 - 16 were shifted 7 units to the right and 3 down.

To find : What would the  new equation be?​

Solution :

Shifting to the right with 'a' unit is

f(x)→f(x-a)

So, shifting g(x) 7 units to the right is

h(x) = 4(x-7)^2-16

Shifting to the down with 'b' unit is

f(x)→f(x)-b

So, shifting g(x) 3 units down is

h(x)=(4(x-7)^2-16)-3

h(x)=4(x-7)^2-19

The new equation is h(x)=4(x-7)^2-19

8 0
2 years ago
I NEED HELP ASAP PLEASE SOLVE FOR X
Marina CMI [18]
ANSWER: x = 130°

EXPLANATION: You must add given angles and then subtract from 180°.
8 0
2 years ago
Which data value has the highest frequency?<br><br> 116<br><br> 316<br><br> 38<br><br> 58
lara31 [8.8K]
1/16.  that is the value that has the most x's on the graph.
8 0
3 years ago
Read 2 more answers
Other questions:
  • What is 160/3 in simplest form
    14·2 answers
  • Solve for x. -0.65 + 0.45x = 5.4
    15·1 answer
  • (25b + 3)(25b – 3)<br> Multiple the binomials.
    13·1 answer
  • Solve the equations<br> x squared + y squared = 36<br> x = 2y + 6
    9·1 answer
  • calculeaza lungimea segmentului ab in fiecare dintre cazuri:A(1,5);B(4,5);A(2,-5),B(2,7);A(3,1)B(-1,4);A(-2,-5)B(3,7);A(5,4);B(-
    6·1 answer
  • Convert 4x=1+2y from standard form to slope intercept form
    8·1 answer
  • For math I need to:<br> Add. 1/3+1/9
    8·2 answers
  • roberto was planning his birthday party. he estimated that each person at his party would eat 2 1/2 hambugers and 1/5 of a bag o
    5·2 answers
  • Is the slope of (-1,5) (-2,6) 2 or is it -1
    7·2 answers
  • Willing to give brainliest to whoever answer this first ​
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!