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ozzi
4 years ago
11

Regarding inferences about the difference between two population means, the sampling design that uses a pooled sample variance i

n cases of equal population standard deviations is based on:_________
Physics
1 answer:
ANEK [815]4 years ago
8 0

Answer:

independent samples.

Explanation:

  • independent samples are randomly selected models so that its findings do not depend on the values ​​of other observations. Many statistical analyzes rely on the assumption that the models are independent. Others are designed to estimate models that are not independent.
  • There are so many independent models that its choices can be randomly selected without relying on the evidence of other observations.

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A heat engine (Power Cycle) with a thermal efficiency of 35 percent efficiency produces 750 kJ of work. Heat transfer to the eng
frosja888 [35]

Answer:

a) The schematic illustrating is attached

b) The heat transfer to the heat engine is 2142.86 kJ, the heat transfer from the heat engine is 1392.86 kJ

c) The heat transfer to the heat engine is 1648.35 kJ, the heat transfer from the heat engine is 898.35 kJ

Explanation:

b) The heat transfer to the engine and the heat transfer from the engine to the air is:

Q_{1} =\frac{W}{n}

Where

W = 750 kJ

n = 35% = 0.25

Replacing:

Q_{1} =\frac{750}{0.35} =2142.86kJ

Q_{2} =Q_{1} -W=2142.86-750=1392.86kJ

c) The efficiency of Carnot engine is:

n=1-\frac{300K}{550K} =0.455

The heat transfer to the heat engine is:

Q_{1c} =\frac{750}{0.455} =1648.35kJ

The heat transfer from the heat engine is:

Q_{2c} =1648.35-750=898.35kJ

4 0
3 years ago
An airplane went from 120 m/s to 180 m/s in 4.0 seconds. What was its acceleration?
scoundrel [369]
<span>15 m/s^2 The first thing to calculate is the difference between the final and initial velocities. So 180 m/s - 120 m/s = 60 m/s So the plane changed velocity by a total of 60 m/s. Now divide that change in velocity by the amount of time taken to cause that change in velocity, giving 60 m/s / 4.0 s = 15.0 m/s^2 Since you only have 2 significaant figures, round the result to 2 significant figures giving 15 m/s^2</span>
3 0
3 years ago
Gunther needs a 75% concentrated solution. When making his solution at room temperature, he could only make a solution that was
jolli1 [7]

Answer:

Heat the solution, dissolve the solute, and let it cool verifying nothing settled out.  

Explanation:

7 0
3 years ago
Read 2 more answers
Different between conventional and non conventional energy sources​
masha68 [24]

CONVENTIONAL SOURCE OF ENERGY:

The conventional sources of energy are generally non-renewable sources of energy, which are being used since a long time. These sources of energy are being used extensively in such a way that their known reserves have been depleted to a great extent.

At the same time it is becoming increasingly difficult to discover and exploit their new deposits. It is envisaged at known deposits of petroleum in our country will get exhausted by the few decades and coal reserves are expected to last for another hundred years. The coal , petroleum, natural gas and electricity are conventional sources of energy.

>Conventional sources of energy are not abundant, present in limited quantity, e.g. coal, petroleum, natural gas.

>conventional source have been in use for a long time.

>conventional source aren’t refill continuously. They are formed over a million years.

>Conventional source are called non-renewable fuel sources of energy.

> Conventional source are mostly used industrial and commercial purposes.

NON-CONVENTIONAL SOURCE OF ENERGY:

Energy generated by using wind, tides, solar geothermal heat and biomass including farm and animal waste as well as human excreta is known as non-conventional energy. All these sources are renewable or inexhaustible and do not cause environment pollution. More over they do not require heavy expenditure.

> Non-conventional sources of energy are abundant in nature, e.g. solar energy, wind energy, tidal energy, bio-gas from biomass etc.

>Non-Conventional source are development phase over the past few years.

>Non-conventional source are continuously fill by natural processes.

>Non-conventional source are called renewable source of energy.

>Non-conventional source are mostly used for household purposes.

7 0
3 years ago
A magnet is pushed into a solenoid of 20 coils with a cross-sectional area of 4.0x10-4 m2. As a result, the magnetic field insid
kobusy [5.1K]

Given:

The number of the coils, N=20

The cross-sectional area of the solenoid, A=4.0×10⁻⁴ m²

The magnetic fields, B₁=0.0500 T

and B₂=0.180 T

The time interval, t=1.90 s

The resistance of the resistor, R=1.90 s

To find:

1. The magnitude of the induced emf.

2. The current flowing through the resistor.

Explanation:

1.

The magnitude of the induced emf in the solenoid is given by,

E=NA\frac{(B_2-B_1)}{t}

On substituting the known values,

\begin{gathered} E=20\times4.0\times10^{-4}\times\frac{(0.180-0.0500)}{1.90} \\ =0.55\times10^{-3}\text{ V} \\ =0.55\text{ mV} \end{gathered}

2.

From Ohm's law, The induced emf is given by,

E=IR

On substituting the known values,

\begin{gathered} 0.55\times10^{-3}=I\times5 \\ \Rightarrow I=\frac{0.55\times10^{-3}}{5} \\ =0.11\times10^{-3}\text{ A} \\ =0.11\text{ mA} \end{gathered}

Final answer:

1. The induced emf is 0.55 mV

2. The current through the given resistor is 0.11 mA

4 0
2 years ago
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