Instructions: For each problem, identify the appropriate test statistic to be use (t test or z-test). Then compute z or t value.
1) A teacher claims that the mean score of students in his class is greater than 82 with a standard deviation of 20. If a sample of 81 students was selected with a mean score of 90 then check if there is enough evidence to support this claim at a 0.05 significance level.
2) An online medicine shop claims that the mean delivery time for medicines is less than 120 minutes with a standard deviation of 30 minutes. Is there enough evidence to support this claim at a 0.05 significance level if 49 orders were examined with a mean of 100 minutes?
3) An English teacher wanted to test whether the mean reading speed of students is 550 words per minute. A sample of 12 students revealed a sample mean of 540 words per minute with a standard deviation of 5 words per minute . At 0.05 significance level, is the reading speed different from 550 words per minute?

The electronic components that could be used in making of energy saving switch are:​

Transistors as  well as other kinds of semiconductor devices are known to be tools or element that can be used in the making of switches. In its use or applications.

Note that the base or gate of a transistor, based  on the kind of transistor that is known to be in use, and it is one that is often employed as a form of control element to be able to switch on as well as switch off the current that often exist between the emitter as well as the collector or the source and that of the drain.

Note also that the electronic components that are able to  store energy in regards to electronic devices, are known to be capacitors and coils (inductors) and they often play a key function of temporarily saving  energy. One key role of a capacitor is to save an electric charge.

Therefore, The electronic components that could be used in making of energy saving switch are:​

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The diameter d of shaft is 0.319m

The actual maximum shear stress of the shaft is 44.95N/m^2

The angle of twist of the 3-m length shaft is 0.01409 rad

The question is incomplete, here is the complete question:

A solid steel shaft 3 m long is transmitting 12 MW at 400 rev/min. The working conditions

to be satisfied by the shaft are:

• The shaft must not twist more than 0.015 radian on a length of 10 times the diameter, i.e., 10D

• The maximum shear stress must not exceed 70 MN/m2.

If the modulus of rigidity of steel is 60 GN/m2 determine:

(a) The diameter of the shaft required

(b) The actual maximum shear stress and the angle of twist of the 3-m length shaft.

Part a

The diameter of the shaft

We use Torque equation to find diameter d:

\(\frac{T}{J} =\frac{G\theta }{L}\)

\(\frac{12*10^{6}*60 }{25600d^{4} } =\frac{60*10^{9}*0.015 }{10d}\)

\(d^{3} =0.032414\)

d=0.319m

Hence, diameter of shaft d=0.319m

Part b

Actual maximum shear stress Y, and the angle of twist of the 3m length shaft

\(Y=\frac{16T}{\pi d^{3} }\)

\(Y=\frac{16*286478.90}{\pi *0.319^{3} }\)

\(Y=44.95N/m^{2}\)

Angle of the twist

Let angle of twist =  \(\theta\)

\(\theta=\frac{TL}{GJ}\)

  \(=\frac{286478.90*3}{60*10^{9}(\frac{\pi }{32}(0.019)^{9} }\)

 =0.01409rad

Angle of twist=0.01409 rad

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It depends on your individual needs and the climate in which you live. Geothermal heat pumps are typically the most efficient and cost effective option, but they are not suitable for all locations.

What is geothermal?

Geothermal energy is a form of renewable energy that comes from the heat generated by the Earth's core. This energy is captured and used to generate electricity, provide heating and cooling, and to create hot water. Geothermal energy has relatively low environmental impact and can be used to meet most of our energy needs. It is a reliable, clean, and safe source of energy that can be used to reduce carbon emissions.  

Air source heat pumps are more widely available and less expensive, but they are not as efficient and are limited by the outdoor temperature. Water source heat pumps are suitable for some climates and can provide more efficient cooling than air source units, but they may be more expensive to install and require a water source such as a pond or lake.

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Answer:

  (i) 12 V in series with 18 Ω.

  (ii) 0.4 A; 1.92 W

  (iii) 1,152 J

  (iv) 18Ω — maximum power transfer theorem

Explanation:

As seen by the load, the equivalent source impedance is ...

  10 Ω + (24 Ω || 12 Ω) = (10 +(24·12)/(24+12)) Ω = 18 Ω

The open-circuit voltage seen by the load is ...

  (36 V)(12/(24 +12)) = 12 V

The Thevenin's equivalent source seen by the load is 12 V in series with 18 Ω.

__

The load current is ...

  (12 V)/(18 Ω +12 Ω) = 12/30 A = 0.4 A . . . . load current

The load power is ...

  P = I^2·R = (0.4 A)^2·(12 Ω) = 1.92 W . . . . load power

__

10 minutes is 600 seconds. At the rate of 1.92 J/s, the electrical energy delivered is ...

  (600 s)(1.92 J/s) = 1,152 J

__

The load resistance that will draw maximum power is equal to the source resistance: 18 Ω. This is the conclusion of the Maximum Power Transfer theorem.

The power transferred to 18 Ω is ...

  ((12 V)/(18 Ω +18 Ω))^2·(18 Ω) = 144/72 W = 2 W

a. Best Critical Region (BCR): The critical region that maximizes the power of a statistical test.

b. Uniformly Most Powerful Test (UMPT): A statistical test with the highest power among all possible tests for a given significance level.

c. Pivotal Quantity (PQ): A function of sample data and an unknown parameter with a known distribution independent of the parameter.

d. Randomized Test: A statistical test where the decision to accept or reject the null hypothesis is determined randomly.

e. Sequential Probability Ratio Test (SPRT): A method for sequential decision-making based on accumulating evidence from a sequence of observations, useful for efficient binary decision-making.

a. The best critical region (BCR) refers to the region in the sample space where the null hypothesis is rejected, resulting in the most favorable trade-off between the probabilities of type I and type II errors. It is the critical region that maximizes the power of the statistical test.

b. The uniformly most powerful test (UMPT) is a type of statistical test that possesses the most power among all possible tests for a given significance level. It is designed to detect the alternative hypothesis with the highest probability, making it the most powerful test in a statistical hypothesis testing framework.

c. A pivotal quantity (PQ) is a function of the sample data and an unknown parameter that has a known distribution that does not depend on the parameter itself. Pivotal quantities are useful in statistical inference as they allow for the construction of confidence intervals and hypothesis tests that are distribution-free or have known distributions.

d. A randomized test is a type of statistical test where the decision to accept or reject the null hypothesis is determined by a random mechanism. It involves using a randomization procedure to assign observations to different treatment groups or to determine the critical region. Randomized tests have the advantage of controlling the type I error rate and can be useful in situations where traditional fixed-sample tests may not be appropriate.

e. The Sequential Probability Ratio Test (SPRT) is a statistical method used for making sequential decisions based on accumulating evidence from a sequence of observations. It is commonly used in quality control and decision-making processes where data is collected sequentially. The SPRT allows for early termination of the test if a decision can be reached with sufficient confidence based on the available data, leading to efficient and timely decision-making. It is particularly useful when testing hypotheses or making binary decisions in a sequential manner, reducing the number of observations required compared to traditional fixed-sample tests.

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Answer:

True

Explanation:

I looked it up

Answer:

true

Explanation:

Answer:

umm okay for starters I have no clue lol.

what is aerodynamics????

Answer:

he/she must have clearance from ATC to proceed and

hold position markings

Explanation:

Answer:

Emails and phone calls are both common forms of communication that are used in professional and personal settings. There are several similarities between email and phone calls:

1. Both are asynchronous forms of communication: Unlike instant messaging or face-to-face conversations, both emails and phone calls allow the sender or recipient to respond at their convenience. They don't require immediate attention or an instant response.

2. Both are written forms of communication: While phone calls rely on spoken words, emails are written. As a result, both can be used to convey detailed information and allow the sender to carefully consider their words before sending.

3. Both are forms of direct communication: Emails and phone calls both allow for direct communication between two parties. This can be beneficial for discussing sensitive information or resolving issues quickly.

4. Both can be used for formal and informal communication: Emails and phone calls can be used in both personal and professional contexts. They are both flexible forms of communication that can be adapted to fit different situations.

5. Both require attention to tone and etiquette: Just like with phone calls, emails require attention to tone and proper etiquette. Both forms of communication should be approached professionally and respectfully to ensure effective communication.

In conclusion, while there are differences between emails and phone calls, there are also similarities that make them useful communication tools. Both allow for direct, asynchronous communication and can be adapted to fit different situations.

Explanation:

Answer:

Check the explanation

Explanation:

Kindly check the attached image below to see the step by step explanation to the question above.

Answer:

Then miss try to get your school to banned it for your district like forbid then from the web site then it will not allow them to use it. then sometimes use it to help other people who needs help like teachers do or we need help with something we dont know so we ask for help for a better understanding of it.

Explanation:

^-^ hope you have a good day miss or sir

Answer:

So I would love to say that you and your team at your school had banned brainly and why are you using brainly here, then you shouldn't use brainly, and brainly all students around the world gets help even you is one.

Answer:

current sales are 15 millon

Explanation:

The efficiency of the motor is 80%.

The heat lost by the motor per minute is 7.5 kW.

The output power of the motor is given by:

P_o = τ * ω

where τ is the torque and ω is the angular velocity.

P_o = 200 N m * (2π * 600 r/min) / 60 s/min = 6000 W

The efficiency of the motor is given by:

η = P_o / P_i

where P_i is the input power.

η = 6000 W / 15 kW = 0.8

The heat lost by the motor per minute is given by:

Q = P_i - P_o

Q = 15 kW - 6000 W = 7.5 kW

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A wrench used to measure resistance while applying a twisting force using a common socket, and whose values are stated in inch-pounds or foot-pounds, is called a; Torque wrench.

The features of the wrench are given as;

The correct answer is Torque wrench because a torque wrench is simply a tool that is used to apply a particular torque to a fastener such as a bolt.

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Answer:

Efficiency is defined as any performance that uses the fewest number of inputs to produce the greatest number of outputs. Simply put, you're efficient if you get more out of less.

Explanation:

Answer:

Diameter of pipe is 0.535 ft

Explanation:

see attachment, its works out 1st half

Answer:

Terminal 2 on a potential relay typically goes to the start winding of a motor.

Explanation:

The potential relay is an electromechanical device used in some types of motors to provide a temporary boost to the starting torque. Terminal 2 is connected to the start winding to assist in starting the motor.

An example of a transducer which can focus at 6 cm is a 4 MHz, near zone length at 10 cm.

A transducer can be defined as a mechanical device that is designed and developed to convert one form of energy to another.

This ultimately implies that, a transducer has the ability to convert a signal in one form of energy to a signal in another energy form such as an ultrasound transducers which converts electric energy into sound energy and vice-versa.

In conclusion, a 4 MHz, near zone length at 10 cm is an example of a transducer which can focus at 6 cm.

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To find the power delivered by the pump, we can use the concept of pump efficiency. The power delivered by the pump is given by the equation:

Power Delivered = Power Input / Efficiency Given: Work done by the impeller (Power Input) = 350 kW Manometric Efficiency = 58% = 0.58 Now, let's calculate the power delivered by the pump: Power Delivered = Power Input / Efficiency Power Delivered = 350 kW / 0.58 Power Delivered ≈ 603.448 kW Therefore, the power delivered by the pump is approximately 603.448 kW. The power delivered by the pump is 603.45 kW. This is calculated by dividing the work done by the impeller (350 kW) by the manometric efficiency (58%) and multiplying by 100The manometric efficiency of a centrifugal pump represents the ratio of the energy imparted to the fluid (work done by the impeller) to the actual energy added to the fluid (power delivered by the pump). It is expressed as a percentage.

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Answer:

false

Explanation:

Answer:

i think D

Explanation:

By applying this transformation to a point represented in frame A, the coordinates of the corresponding point in frame B can be found. The sequence of transformations involves translation along the Y-axis and Z-axis of A, followed by a rotation of B about the Z-axis of A.

To determine the homogeneous coordinate transformation matrix, we can first construct the translation matrix for the given translations. The translation along the Y-axis of A by 5 units can be represented as [1, 0, 5], and the translation along the Z-axis of A by 7 units can be represented as [0, 1, 7]. These translations can be combined into a 4x4 translation matrix. Next, we can construct the rotation matrix for the rotation of B about the Z-axis of A by 900. This rotation corresponds to a transformation matrix of the form:

R = [[cos(900), -sin(900), 0, 0],

[sin(900), cos(900), 0, 0],

[0, 0, 1, 0],

[0, 0, 0, 1]]

Multiplying the translation matrix by the rotation matrix gives us the homogeneous coordinate transformation matrix. To find the coordinates of the corresponding point in frame B, we can multiply the transformation matrix by the given point [Y]A = [0, 10, 0, 1]T. The resulting coordinates will be in the B frame. Graphically, the transformations involve translating the point along the Y-axis and Z-axis of frame A and then rotating frame B about the Z-axis of A. These transformations change the position and orientation of the B frame relative to the A frame, resulting in the corresponding point being expressed in the B frame.

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For air at 20 degrees C and 1 atm is driven between two parallel plates 1 cm apart by an imposed pressure gradient (dp/dx) and by the upper plate's moving at 20 cm/s, assuming unit depth, The volumetric flow rate is found to be 0.00002 m^3/s and the value of dp/dx (in Pa/m) which causes the shear stress at the lower plate to be zero is 0 Pa/m.

(a) To find the volumetric flow rate, we can use the equation:

Q = A * V

where Q is the volumetric flow rate, A is the cross-sectional area of the flow, and V is the velocity of the flow.

Given:

Distance between plates (d) = 1 cm = 0.01 m

The velocity of the upper plate (V) = 20 cm/s = 0.2 m/s

To calculate the cross-sectional area (A), we can use the formula for the area of a rectangle:

A = d * w

where w is the width of the channel.

Assuming unit depth, the width of the channel is equal to the distance between the plates (d).

A = 0.01 m * 0.01 m = 0.0001 m^2

Now we can calculate the volumetric flow rate (Q):

Q = A * V = 0.0001 m^2 * 0.2 m/s = 0.00002 m^3/s

Therefore, the volumetric flow rate is 0.00002 m^3/s.

(b) To find the value of dp/dx that causes the shear stress at the lower plate to be zero, we need to consider the no-slip condition, which states that the velocity of the fluid at the solid boundary is equal to the velocity of the boundary itself. In this case, the lower plate is stationary, so its velocity is 0 m/s.

The shear stress (τ) can be calculated using the formula:

τ = μ * (du/dy)

where μ is the dynamic viscosity of air and (du/dy) is the velocity gradient.

Since the shear stress at the lower plate is zero, we can set τ = 0:

0 = μ * (du/dy)

Since the lower plate is stationary, (du/dy) = 0. Therefore, the velocity gradient is zero.

The velocity gradient (du/dy) can be related to the pressure gradient (dp/dx) by the equation:

dp/dx = -μ * (du/dy)

To find the value of dp/dx that causes the shear stress at the lower plate to be zero, we need to find the pressure gradient that makes (du/dy) = 0.

Therefore, the value of dp/dx that causes the shear stress at the lower plate to be zero is 0 Pa/m.

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To prevent aliasing, the anti-aliasing filter's cutoff frequency should be less than half of the sampling frequency (Nyquist frequency). Therefore, for a signal to be sampled at 1 kHz, the cutoff frequency of the anti-aliasing filter should be less than 500 Hz.

When sampling an analog signal, it is important to ensure that the resulting digital signal accurately represents the original signal. Aliasing can occur when the signal is not properly sampled, resulting in distortion or errors in the digital signal.

To prevent aliasing, an anti-aliasing filter is used to remove any frequency components above the Nyquist frequency, which is half the sampling rate. In this case, the signal is to be sampled at 1 kHz, so the Nyquist frequency is 500 Hz.

Therefore, the cutoff frequency of the anti-aliasing filter should be set at or below 500 Hz to prevent any frequency components above the Nyquist frequency from being sampled and causing aliasing. A good rule of thumb is to set the cutoff frequency at about 70% of the Nyquist frequency, so a cutoff frequency of around 350 Hz would be appropriate in this case.

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The brainstorming design process typically does not involve seven stages that specifically include building a model and creating a preventive maintenance plan.The correct answer is option False.

The stages involved in the brainstorming design process may vary depending on the specific context and industry, but they generally follow a similar framework.

Here is a more commonly recognized and concise outline of the brainstorming design process:

1. Identify the problem or opportunity: Clearly define the problem or identify the opportunity that needs to be addressed through the design process.

2. Research and gather information: Conduct research and collect relevant data, information, and resources to gain a better understanding of the problem and potential solutions.

3. Generate ideas: Engage in brainstorming sessions or other creative techniques to generate a wide range of ideas and potential solutions.

4. Evaluate and select ideas: Evaluate the generated ideas based on criteria such as feasibility, practicality, and alignment with project goals. Select the most promising ideas for further development.

5. Develop prototypes: Create prototypes or mock-ups to visualize and test the selected ideas. This stage focuses on creating tangible representations of the design concepts.

6. Test and iterate: Test the prototypes and gather feedback from users or stakeholders. Use the feedback to refine and improve the design.

7. Finalize and implement: Incorporate the feedback and make final adjustments to the design. Prepare the design for implementation or production.

The stages mentioned in your response, building a model and creating a preventive maintenance plan, are not typically considered core components of the brainstorming design process.

However, they might be relevant in specific contexts or industries, such as engineering or product development, where a detailed design process is required, including modeling and maintenance planning.

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Using the knowledge in computational language in python it is possible to write a code that output the number of characters excluding the three characters commonly used for end-of-sentence punctuation.

   import re

   def check_sentence(text):

     result = re.search(r"^[A-Z][A-Za-z\s]*[\.\?!]$", text)

     return result != None

   print(check_sentence("Is this is a sentence?")) # True

   print(check_sentence("is this is a sentence?")) # False

   print(check_sentence("Hello")) # False

   print(check_sentence("1-2-3-GO!")) # False

   print(check_sentence("A star is born.")) # True

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