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
Margaret [11]
3 years ago
15

In order to fairly set flat rates for auto mechanics, a shop foreman needs to estimate the average time it takes to replace a fu

el pump in a car. How large a sample must he select if he wants to be 90% confident that the average time is within 20 minutes of the sample average? Assume the standard deviation of all times is 40 minutes.
Mathematics
1 answer:
Ede4ka [16]3 years ago
4 0

Answer:

ME = 1.96(45)/sqrt(n) 25 = 1.96(45)/sqrt(n) n = (1.96(45)/25)^2 = 6

Step-by-step explanation:

yw

You might be interested in
HELPPPPP ASAPPPP!!!!!!
In-s [12.5K]

Hey there!!

Let's take the number as x and y

Given,

The sum of x and y = 12

One number is 2 more than the other

Let's take y = x + 2

Equations

x + y = 12

As we know y = x + 2 , plug the value in

x + x + 2 = 12

2x + 2 = 12

Subtract 2 on both sides

2x = 10

Divide by 5 on both sides

x = 5

y = 2 + x

y = 7

The numbers are 5 and 7

Hope my answer helps!

3 0
3 years ago
Read 2 more answers
Alejandro Juarez is paid $829 every two weeks. How much would Alejandro earn in 4 weeks ?
aev [14]

Answer:

$1,658 in 4 weeks

Step-by-step explanation:

Since we are working in intervals of 2, we can just multiply.

829 * 2

1658

Best of luck!

6 0
4 years ago
Read 2 more answers
A random sample of 77 fields of corn has a mean yield of 26.226.2 bushels per acre and standard deviation of 2.322.32 bushels pe
PSYCHO15rus [73]

Answer:

Therefore the  95% confidence interval is (25,707.480 < E < 26,744.920)

Step-by-step explanation:

n = 77

mean u = 26,226.2  bushels per acre

standard deviation s = 2,322.32

let E = true mean

let A = test statistic

Find 95% Confidence Interval

so

let  A =  (u - E) *  (\sqrt{n}  / s)   be the test statistic

we want      P( average_l <  A  < average_u )  = 95%

look for  lower 2.5%  and the upper 97.5%  Because I think this is a 2-tail test

average_l =  -1.96  which corresponds to the 2.5%

average_u = 1.96

P(  -1.96  <  A  <  1.96)  =  95%

P(  -1.96  <  (u - E) *  (\sqrt{n}  / s)  <  1.96)  =  95%

Solve for the true mean E ok

E   <   u + 1.96* (s  / \sqrt{n})

from  -1.96  <  (u - E) *  (\sqrt{n}  / s)

E < 26,226.2 +  1.96*( 2,322.32 / \sqrt{77} )

E < 26,226.2 +  1.96*( 2,322.32 / \sqrt{77} )

E < 26,226.2 +  518.7197348105429466

upper bound is 26,744.9197

or

u - 1.96* (s  / \sqrt{n})  < E

26,226.2 -  518.7197348105429466  < E

25,707.48026519  < E

lower bound is 25,707.48026519

Therefore the  95% confidence interval is (25,707.480 < E < 26,744.920)

7 0
3 years ago
Can you guys please help me I would really appreciate it thank you so much! :)
ASHA 777 [7]

Answer:

I'll attach a photo of my answers. I can also provide work if needed, but based on this photo, it looks like an online quiz so I won't waste my time with that.

I hope this helps! Feel free to give me Brainliest if you feel this helped. Have a good day, good luck on your assignment. :)

6 0
3 years ago
Read 2 more answers
Y=x^2+3x+54 what is the table?
andrew11 [14]

Answer:

i added an attachment of the graph :)

Step-by-step explanation:

7 0
3 years ago
Other questions:
  • How many different books did the children read
    5·1 answer
  • n the sequence $121, 1221, 12221, \dots ,$ the $n$th number consists of $n$ copies of the digit $2$, surrounded by two $1$s. How
    5·2 answers
  • Find the height, round to the nearest hundredth<br>Area is 72units squared <br>​
    9·1 answer
  • PLEASE ANSWER THIS RIGHT!! TODAYS MY LAST DAY TO DO THIS
    15·1 answer
  • Factor the following:<br><br> x2-17x+60
    11·1 answer
  • The maximum or minimum point of a parabola is called the __________.
    15·1 answer
  • Help me please, I want the answer only.
    7·1 answer
  • Some help please? No links or I will report.
    5·2 answers
  • Determine which equation below have x = 15 as a solution.
    11·2 answers
  • C is the circumcenter of isosceles triangle ABD with vertex angle ABD. Does the following proof correctly justify that triangles
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!