Mathematics, 25.04.2020 00:52 Boondiddy9

Lazurus Steel Corporation produces iron rods that are supposed to be 36 inches long. The machine that makes these rods does not produce each rod exactly 36 inches long. The lengths of these rods vary slightly. It is known that when the machine is working properly, the mean length of the rods made on these machine is 36 inches. The standard deviation of the lengths of all rods produced on this machine is always equal to .10 inches. The quality control department takes a sample of 40 such rods every week, calculates the mean length of these rods, and makes 99% confidence interval for the population mean. If either the upper limit of this confidence interval is greater than 36.05 inches or the lower limit of this confidence is less than 35.95 inches, the machine is stopped and adjusted. A recent such sample of 40 rods produced a mean length of 36.02 inches. Based on this sample, will you conclude that the machine needs an adjustment? What is the predominant formula you will use to solve the problem?

Answers: 1

Show answers

Answers

Answer from: imthatsavageboi

Step-by-step explanation:

We would construct a confidence interval.

Confidence interval is written in the form,

(Sample mean - margin of error, sample mean + margin of error)

The sample mean, x is the point estimate for the population mean.

Since the sample size is large and the population standard deviation is known, we would use the following formula and determine the z score from the normal distribution table.

Margin of error = z × σ/√n

Where

σ = population standard Deviation

n = number of samples

From the information given

x = 36.02 inches

σ = 0.1 inches

n = 40

To determine the z score, we subtract the confidence level from 100% to get α

α = 1 - 0.99 = 0.01

α/2 = 0.01/2 = 0.005

This is the area in each tail. Since we want the area in the middle, it becomes

1 - 0.005 = 0.995

The z score corresponding to the area on the z table is 2.58. Thus, confidence level of 99% is 2.58

Margin of error = 2.58 × 0.1/√40 = 0.041

Confidence interval = 36.02 ± 0.041

The lower end of the confidence interval is

36.02 - 0.041 = 35.979 inches

The upper end of the confidence interval is

36.02 - 0.041 = 36.061 inches

Since 36.061 > 36.05, then we would conclude that the machine needs an adjustment.

The formula used is

Confidence interval =

Sample mean ± z × σ/√n

Answer from: Quest

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

= $\sqrt{(9-6)^{2} +(12-6)^{2} } \\=\sqrt(45)=3\sqrt(5)$

side j'k'=distance between j' and k'

= $\sqrt{(3-2)^{2} +(2-4)^{2} } \\=sqrt(5)$

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl

Answer from: Quest

First, think of what you know. you know that the number t the end of the equation will need to be subtracted because it is the money he lost from buying the lawn mower. and your first two weeks have negative profit, so that tells you that c and d are wrong. now you can plug any of the weeks into a and b to see which one works. i'll start with plugging week 1 into a. $y = 60(1) - 90 \\ y = 60 - 90 \\ y = - 30$ this isn't right because it says your answer for week one should be -90.so now we need to try the same thing with b. $y = 60(1) - 150 \\ y = 60 - 150 \\ y = - 90$ this one got you the right answer, (sometimes if you only check with one of the weeks multiple will work so you need to check with more of the weeks, but it worked out fine here)this means that b is the correct answer.let me know if you need more clarification. i hope this : )

Another question on Mathematics

Mathematics, 21.06.2019 12:30

Convert 16 yards to feet use the conversion rate 3 feet = 1 yard

Answers: 2

Answer

Mathematics, 21.06.2019 20:20

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?

Answers: 1

Answer

Mathematics, 21.06.2019 22:00

Question 13 (1 point) jerome is starting a new job. his contract states he will earn $42,000 the first year, and will get a 4% raise per year. which function s(x) represents jerome's salary after a certain number of years, x?

Answers: 1

Answer

Mathematics, 21.06.2019 22:30

Select all of the following expressions that are equal to 2.5.

Answers: 3

Answer

You know the right answer?

Lazurus Steel Corporation produces iron rods that are supposed to be 36 inches long. The machine tha...

Questions