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
dezoksy [38]
3 years ago
7

The life in hours of a thermocouple used in a furnace is known to be approximately normally distributed, with standard deviation

σ = 20 hours. A random sample of 15 thermocouples resulted in the following data: 553, 552, 567, 579, 550, 541, 537, 553, 552, 546, 538, 553, 581, 539, 529. We wanted to be 95% confident that the error in estimating the mean life is less than 5 hours. What sample size should we use? Round z-value to two decimal places in your intermediate calculations. Round your answer up to the nearest whole number.

Mathematics
1 answer:
Effectus [21]3 years ago
8 0

Answer:

62 is the minimum sample size needed

Step-by-step explanation:

We know that the population is approximately normally distributed so we will use a z-score for 95% confidence, which is 1.96.  We are given the population standard deviation of σ = 20, and are given that the error should be 5 or less hours.  The fact that it gives us sample data is irrelevant since we are told the population is approximately normally distributed and are given the population standard deviation.

See the attached photo for the calculation of the minimum sample size

You might be interested in
Complete the solution of the equation. Find the value of y when x equals 15.
Mariulka [41]

Answer:

y = -6   PLEASE GIVE BRAINLIEST

Step-by-step explanation:

-15 - 9y = 39

               39 + 15 = 54

-9y =54

y = 54 ÷ -9 = -6

y = -6

8 0
2 years ago
Which of the following correctly describes the end behavior of the polynomial function, f(x) 3x^4 +2x^2 -x? A. The left end goes
ozzi
I think it’s A but I’m not 100%
8 0
2 years ago
Read 2 more answers
Please help this is due tomorrow morning
Minchanka [31]

Answer:

I can try to help you..uhh alright 1ll it's definitely multiplying by 4 on the bottom but adding 1 one the top. I'm not sure if i'll be correct but try 1 and 4 i'm so sorry if it doesn't help!

7 0
3 years ago
The expression to find the perimeter of a rectangle is 2(length + width). What is the perimeter, in units, of a rectangle of len
Allisa [31]
First you plug in the data to the formula. So it will be 2(1/3+1/2). You then want to add the fractions together but must first find the common denominator which will be 6. So it is 2(2/6+3/6). The fractions then add up to be 5/6. So all you have to do is multiply it by 2 to get 5/3 which simplifies to 1 2/3 so it is D. 
4 0
2 years ago
Read 2 more answers
Divide using long division. Checky<br> (x3+ 3x2 + x - 9) = (x - 1)
Montano1993 [528]

Answer:

x squared plus 2x minus 1.

Step-by-step explanation:

x3+3x2+x-9 is in the division "house" and x-1 is on the outside. xsquare times x equals x cubed. and x square times negative 1 equals -x squsre. put x square on top of the roof. change the signs. the x cubed cancels out. and bring down 2x square from subtracting 3x square and -x square and bring down the x-9. Put 2x on top of the roof too and 2x times x equals 2x square and multiply by -1. U will have 2x square -2x square and -2x plus x which equals -1x cuz the 2x square cancels out. bring down the -9. Now i have -1x-9. Multiply by -1 and put -1 on the roof. -1x+1x cancels out. and -1 times -1 equals positive 1. So -9+1=8. U van do any further cause as soon as the last number is at the end of the roof and u cant go further, ur done dividing. so the answer is x square+2x-1/×-1 +8 as the remainder. hope i helped

6 0
2 years ago
Other questions:
  • Write the equation in exponential form log4 1/6=-2
    10·1 answer
  • Quadrilateral ABCD is dilated to form quadrilateral A′B′C′D′. Which statement is true?
    7·1 answer
  • A bag contains both black and red marbles. The ratio of black to red marbles is 3:4.
    12·1 answer
  • 53.02 in expanded notation
    15·2 answers
  • camila is working two summer jobs,making $10 per hour lifeguarding and $6 per hour walking dogs. Camila worked 5 more hours life
    10·1 answer
  • Coach Joel recorded the amount of time his runners take to run a mile in practice. If, on average, they can run it in under 7 mi
    7·2 answers
  • HELP PLS I DONT GET THIS WILL GIVE BRAINLIEST
    8·2 answers
  • Sarah reads 51 pages in 17 days.
    5·2 answers
  • Im going to give brainly plz help me thx i promise.
    8·2 answers
  • HELP FAST ANYONE OLEASE I HAVE LIKE 2 minutes too answer !!
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!