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Marizza181 [45]
3 years ago
9

It costs more to produce defective items - since they must be scrapped or reworked - than it does to produce non-defective items

. This simple fact suggests that manufacturers should ensure the quality of their products by perfecting their production processes instead of depending on inspection of finished products (Deming, 1986). In order to better understand a particular metal stamping process, a manufacturer wishes to estimate the mean length of items produced by the process during the past 24 hours.(Give answer to nearest whole number.)a) How many parts should be sampled in order to estimate the population mean to within .1 millimeter (mm) with 90% confidence? Previous studies of this machine have indicated that the standard deviation of lengths produced by the stamping operation is about 2mm.
Mathematics
1 answer:
Shtirlitz [24]3 years ago
5 0

Answer:

1,082

Step-by-step explanation:

The sample size n in Simple Random Sampling is given by

\bf n=\frac{z^2s^2}{e^2}

where  

z = 1.645 is the critical value for a 90% confidence level (*)

s = 2 is the estimated population standard deviation

e = 0.1 mm points is the margin of error

so  

\bf n=\frac{z^2s^2}{e^2}=\frac{(1.645)^2(2)^2}{(0.1)^2}=1,082.22\approx 1,083

rounded up to the nearest integer.

So the manufacturer should test 1,083 parts.

---------------------------------------------------------------------------------------

(*)This is a point z such that the area under the Normal curve N(0,1) outside the interval [-z, z] equals 10% = 0.1

It can be obtained in Excel with

NORMINV(1-0.05,0,1)

and in OpenOffice Calc with

NORMINV(1-0.05;0;1)

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Find the perimeter of the figure to the nearest hundredth.
Kobotan [32]

Answer:

65.12 mm

Step-by-step explanation:

Circumference of semicircle = 8π mm

Perimeter = (40 + 8π) = 65.12 mm

7 0
3 years ago
7. a hockey arena has 10 920 seats. the first row of seats around the rink has 220 seats. the number of seats in each subsequent
Mazyrski [523]

The number of rows in the arena is 26

<h3>How to determine the number of rows?</h3>

The hockey arena illustrates an arithmetic sequence, and it has the following parameters:

  • First term, a = 220
  • Sum of terms, Sn = 10920
  • Common difference, d = 16

The number of rows (i.e. the number of terms) is calculated using:

S_n = \frac{n}{2}(2a + (n -1) * d)

So,we have:

10920 = \frac{n}{2}(2 * 220 + (n -1) * 16)

Evaluate the terms and factors

21840 = n(440 + 16n -16)

Evaluate the like terms

21840 = n(424+ 16n)

Expand

21840 = 424n + 16n^2

Rewrite as:

16n^2 + 424n - 21840 = 0

Using a graphical tool, we have:

n = 26

Hence, the number of rows in the arena is 26

Read more about arithmetic sequence at:

brainly.com/question/6561461

#SPJ1

4 0
2 years ago
Will Mark brainliest if answer both correctly / What is X= ? / conditional statement
harkovskaia [24]
The answer is for 1st question is “10.4” and for the second question “non of these choices are correct”.

Explanation:

For the 1st question:

tan = opposite / adjacent

tan 30 = x / 18

18 tan 30 = x

x = 10.4

For the 2nd question,
If a triangle as an angle of 90 degree, it is 100% a right triangle.

Hope it helps :), mark me brainliest please!
6 0
3 years ago
Use the quadratic formula to find the roots: -3x^2 + 27x = 42​
ch4aika [34]

Answer:

x=2,x=7

Step-by-step explanation:

-3x^2+27x=42

x^2-9x+14=0

x^2-2x-7x+14=0

x*(xi2)-7(x-2)=0

(x-2)*(x-7)=0

x-2=0

x-7=0

x=2

x=7

8 0
3 years ago
Over the summer, Mr. Patel refilled a bird feeder 24 times using 6 cups of seed each time. A bag of seeds holds 32 cups. How man
Illusion [34]

Mr. Patel used 4.5 bags of seed

<em><u>Solution:</u></em>

Given that,

Over the summer, Mr. Patel refilled a bird feeder 24 times using 6 cups of seed each time

A bag of seeds holds 32 cups

1 bag of seed = 32 cups

Given that Patel refilled 24 times using 6 cups of seed each time

<em><u>Then, the number of cups used for the 24 times  is given as:</u></em>

6 \times 24 = 144

<em><u>Now we have to find the bags of seed needed for 144 cups</u></em>

Let "x" be the number of bags of seed for 144 cups

From given,

1 bag of seed = 32 cups

"x" bags of seed = 144 cups

This forms a proportion and we can solve it by cross multiplying

144 \times 1 = 32 \times x\\\\144 = 32x\\\\x = \frac{144}{32}\\\\x = 4.5

Thus 4.5 bags of seed is used by Mr.patel

5 0
3 years ago
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