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dalvyx [7]
3 years ago
8

A random sample of 85 group leaders, supervisors, and similar personnel at General Motors revealed that, on average, they spent

6.5 years in a particular job before being promoted. The standard deviation of the sample was 1.7 years. Construct a 95% confidence interval.
Mathematics
1 answer:
andreyandreev [35.5K]3 years ago
4 0

Answer:

Step-by-step explanation:

From the information given,

Number of personnel sampled, n = 85

Mean or average = 6.5

Standard deviation of the sample = 1.7

We want to determine the confidence interval for the mean number of years that personnel spent in a particular job before being promoted.

For a 95% confidence interval, the confidence level is 1.96. This is the z value and it is determined from the normal distribution table. We will apply the following formula to determine the confidence interval.

z×standard deviation/√n

= 1.96 × 6.5/√85

= 1.38

The confidence interval for the mean number of years spent before promotion is

The lower end of the interval is 6.5 - 1.38 = 5.12 years

The upper end is 6.5 + 1.38 = 7.88 years

Therefore, with 95% confidence interval, the mean number of years spent before being promoted is between 5.12 years and 7.88 years

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WITCHER [35]

Answer:

764

Step-by-step explanation:

well, it is

4 0
2 years ago
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A balloon has a circumference of 28 in use the circumference to approximate the surface area of the ballon to the nearest square
nikklg [1K]

The surface area of the balloon is 249 in².

<h3>What is the surface area of the balloon ?</h3>

A balloon has the shape of a sphere. The distance round the sphere is equal to the circumference of the sphere.

Circumference of the sphere = 2πr

Where:

  • r = radius
  • π = pi = 22 / 7

Radius - circumference / 2π

28 / ( 2 x 22/7) = 4.45 inches

Surface area of a sphere = 4πr²

4 x 22/7 x 4.45² = 249 in²

To learn more about the surface area of a sphere, please check: brainly.com/question/27267844

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5 0
1 year ago
Need an answer as soon as possible.
Elza [17]
Part A

Answer: The common ratio is -2

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

Explanation: 

To get the common ratio r, we divide any term by the previous one

One example:
r = common ratio
r = (second term)/(first term)
r = (-2)/(1)
r = -2

Another example:
r = common ratio
r = (third term)/(second term)
r = (4)/(-2)
r = -2
and we get the same common ratio every time

Side Note: each term is multiplied by -2 to get the next term

============================================================
Part B

Answer:
The rule for the sequence is 
a(n) = (-2)^(n-1)
where n starts at n = 1

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

Explanation:

Recall that any geometric sequence has the nth term
a(n) = a*(r)^(n-1)
where the 'a' on the right side is the first term and r is the common ratio

The first term given to use is a = 1 and the common ratio found in part A above was r = -2
So,
a(n) = a*(r)^(n-1)
a(n) = 1*(-2)^(n-1)
a(n) = (-2)^(n-1)

============================================================
Part C

Answer: The next three terms are 16, -32, 64

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

Explanation:

We can simply multiply each previous term by -2 to get the next term. Do this three times to generate the next three terms

-8*(-2) = 16
16*(-2) = -32
-32*(-2) = 64

showing that the next three terms are 16, -32, and 64

An alternative is to use the formula found in part B

Plug in n = 5 to find the fifth term
a(n) = (-2)^(n-1)
a(5) = (-2)^(5-1)
a(5) = (-2)^(4)
a(5) = 16 .... which matches with what we got earlier

Then plug in n = 6
a(n) = (-2)^(n-1)
a(6) = (-2)^(6-1)
a(6) = (-2)^(5)
a(6) = -32 .... which matches with what we got earlier

Then plug in n = 7
a(n) = (-2)^(n-1)
a(7) = (-2)^(7-1)
a(7) = (-2)^(6)
a(7) = 64 .... which matches with what we got earlier

while the second method takes a bit more work, its handy for when you want to find terms beyond the given sequence (eg: the 28th term)
6 0
3 years ago
We can use special triangles to solve for x in triangle A<br>true or false​
KIM [24]
I believe the answer is false.

explanation: a special triangle has side lengths of 3-4-5 or 6-8-10. In this case since you have 10 one of the other sides would have to be 6 or 8. You can use pythagorean theorem.
8 0
2 years ago
Plot two points to graph the equation.<br><br> y=−1/3x+1
Viktor [21]

Answer:

(3,0) & (-6,3)

Step-by-step explanation:

-1/3(3)+1= -1+1=0

-1/3(-6)+1= 2+1= 3

8 0
3 years ago
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