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Troyanec [42]
3 years ago
10

A researcher estimates the 90% CI for a sample with a mean of M = 8.9 and a standard error (sigma_M) of 2.1. What is the confide

nce interval at this level of confidence?
Mathematics
1 answer:
Shalnov [3]3 years ago
4 0

Answer:

The confidence interval at this level of confidence is between 5.4455 and 12.3545.

Step-by-step explanation:

We have that to find our \alpha level, that is the subtraction of 1 by the confidence interval divided by 2. So:

\alpha = \frac{1-0.9}{2} = 0.05

Now, we have to find z in the Ztable as such z has a pvalue of 1-\alpha.

So it is z with a pvalue of 1-0.05 = 0.95, so z = 1.645

Now, find M as such

M = z*s

In which s is the standard deviation of the sample, which is also called standard error. So

M = 1.645*2.1 = 3.4545

The lower end of the interval is the sample mean subtracted by M. So it is 8.9 - 3.4545 = 5.4455

The upper end of the interval is the sample mean added to M. So it is 8.9 + 3.4545 = 12.3545

The confidence interval at this level of confidence is between 5.4455 and 12.3545.

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Explain wether the graph represents a function.
frosja888 [35]

Answer:

The vertical line test can be used to determine whether a graph represents a function. ... If we can draw any vertical line that intersects a graph more than once, then the graph does not define a function because that x value has more than one output. A function has only one output value for each input value.

4 0
2 years ago
In triangle ABC,if measure of angle A is seven more than four times measure of angle B and measure of angle C is eleven more tha
Yuri [45]

Answer: Angle A is 115 degrees

Step-by-step explanation:

In triangle ABC, the measure of angle A is seven more than four times measure of angle B. This means that

Angle A = 4(Angle B) + 7

The measure of angle C is eleven more than measure of angle B. This means that

Angle C = Angle B + 11.

The equations are

A = 4B + 7 - - - - - - - - 1

C = B + 11 - - - - - - - - - - 2

Recall that the sum of the angles in a triangle is 180 degrees. This means that

A + B + C = 180 degrees

Substituting equation 1 and equation 2 into A + B + C = 180, it becomes

4B + 7 + B + B + 11 = 180

6B + 18 = 180

6B = 180 - 18 = 162

B = 162/6 = 27 degrees

Substituting B = 27 into equation 1, it becomes

A = 4×27 + 7 = 108 +7

A = 115 degrees

Substituting B = 27 into equation 2, it becomes

C = 27 + 11

C = 38 degrees

Sum of the angles is 115 + 27 + 38 = 180

7 0
3 years ago
If 25% of a number is 45, is the number greater or less than 45? Explain your answer. (Hint: You might want to solve to find wha
Sophie [7]

Answer:

Greater

Step-by-step explanation:

A number must be greater that a small percentage of the number

Greater

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

45% = 0.45

.45 x = 45

Divide both sides by .45

x = 100

5 0
3 years ago
If a ball is thrown in the air with a velocity 52 ft/s, its height in feet t seconds later is given by y = 52t - 16t^2. Find the
Sunny_sXe [5.5K]

Answer:

a.) -20ft/s

b.) -13.6ft/s

c.) -12.8ft/s

d.) -12.16ft/s

e.) -12ft/s

Step-by-step explanation:

Average Velocity = Change in distance/change in time.

Distance from the question in given in form of t as y= 52t - 16t² If our initial time is 2, distance travelled at t=2 is given as

Y(2) = 52(2) - 16(2)² =104 - 64

Y = 40ft.

For question a, when change In t is 0.5 seconds, that is from 2 sec to 2.5 seconds,

Average velocity = y(2.5) - y(2)/0.5

y(2.5) = 52(2.5) - 16(2.5)² =130 - 100 = 30

Y(2) = 40

Average velocity in 0.5 seconds = [30 - 40]/0.5 = -20ft/s.

For question b, when change In t is 0.1 seconds, that is from 2 sec to 2.1 seconds,

Average velocity = y(2.1) - y(2)/0.1

y(2.1) = 52(2.1) - 16(2.1)² =109.2 - 70.56= 38.64

Y(2) = 40,

Average velocity in 0.1 seconds = [38.64 - 40]/0.1 = -13.6ft/s.

For question c, when change In t is 0.05 seconds, that is from 2 sec to 2.05 seconds,

Average velocity = y(2.05) - y(2)/0.05

y(2.05) = 52(2.05) - 16(2.05)² = 106.6 - 67.24 = 39.36

Y(2) = 40

Average velocity in 0.05 seconds = [39.36 - 40]/0.05 = -12.8ft/s.

For question d, when change In t is 0.01 seconds, that is from 2 sec to 2.01 seconds,

Average velocity = y(2.01) - y(2)/0.01

y(2.01) = 52(2.01) - 16(2.01)² = 104.52 -64.6416 = 39.8784

Y(2) = 40

Average velocity in 0.5 seconds = [39.8784 - 40]/0.01 = -12.16ft/s.

Instantaneous velocity at t =2 is derived by getting the first derivative of y and inserting Our value of t=2 into the first derivative.

If y = 52t - 16t², then derivative of y becomes y' given as

y'= 52 - 32t

At t = 2,

y'= 52 - 32(2) = 52 - 64 = - 12ft/s.

Instantaneous velocity at t=2 is given as -12ft/s.

5 0
4 years ago
The picture below shows a container that Rene uses to freeze water: A cylinder is shown with base diameter of 6 centimeters and
Rama09 [41]

it would be 9.

2000/226.2 = 8.84 == 9

4 0
3 years ago
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