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Fudgin [204]
2 years ago
14

It is known that the population mean for the verbal section of the SAT is 500 with a standard deviation of 100. In 2006, a sampl

e of 400 students whose family income was between $70,000 and $80,000 had an average verbal SAT score of 511. The point estimate of the mean for this group is _____ and the 95 percent confidence interval for this group is _____.
Physics
1 answer:
kvasek [131]2 years ago
4 0

Answer

given,

SAT is 500 with a standard deviation of 100.

a sample of 400 students whose family income was between $70,000 and $80,000 had an average verbal SAT score of 511.

sample mean = \dfrac{standard\ deviation}{\sqrt{n}}

                      = \dfrac{100}{\sqrt{400}}

                      = 5

95% confidence level is achieved within +/- 1.960 standard deviations.

1.960 standard deviations  x  5 is equal to +/- 9.8

confidence interval = 511 - 9.8   ---  511 + 9.8

                                = 501.2-----520.8

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2 years ago
Solve this physics for me <br>please with steps<br>​
Mars2501 [29]

Answer:

The answers are located in each of the explanations showed below

Explanation:

a)

(i) Surface Tension: The tensile force that causes this tension acts parallel to the surface and is due to the forces of attraction between the molecules of the liquid. The magnitude of this force per unit of length is called surface tension.

σ = F/l [N/m]

where:

F = force [N]

l = length [m]

σ = Surface Tension [N/m]

(ii) Frequency is the number of repetitions per unit of time of any periodic event.

f = 1/T [1/s] or [s^-1] or [Hz]

where:

T = period [s] or [seconds]

f = frecuency [Hz] or [hertz]

(iii) Each of the units will be shown for each variable

v = velocity [m/s]

a = accelertion [m/s^2]

s = displacement [m]

[\frac{m}{s} ]^{2} =[\frac{m}{s} ]^{2} + 2* [\frac{m}{s^{2} } ]*[m]\\

[\frac{m^2}{s^2} ] =[\frac{m^2}{s^2} ] +  [\frac{m^{2} }{s^{2} } ]

[\frac{m^2}{s^2} ]

b) To find the velocity we must derivate the function X with respect to t because this derivate will give us the equation for the velocity, it means:

v=\frac{dx}{dt} \\v = 0.75*2*t+5*t

(i) X = 0.75*t^{2} +5*t+1\\X = 0.75*(4)^{2} +5*(4)+1\\X = 33 [m]

ii) replacing in the derivated equation.

v=1.5*(4)+5\\v=11[m/s]

iii) the average velocity is defined by the expresion v = x/t

v = \frac{x-x_{0} }{t-t_{0} } \\

x_{0}=0.75(2)^{2}+5(2)+1 \\ x_{0}=14[m]\\x=0.75(7)^{2}+5(7)+1\\x=72.75[m]\\t = 7 [s]t0= 2[s]Now replacing:[tex]v_{prom} = \frac{72.75-14}{7-2} \\v_{prom} = 11.75 [m/s]

2

a) Pascal's principle or Pascal's law, where the pressure exerted on an incompressible fluid and in balance within a container of indeformable walls is transmitted with equal intensity in all directions and at all points of the fluid.

Therefore:

P1 = pressure at point 1.

P2 = pressure at point 2.

P1 = F1/A1

P2= F2/A2

\frac{F_{1} }{A_{1} }=\frac{F_{2}}{A_{2} }  \\F_{1}=A_{1}*(\frac{F_{2}}{A_{2} })

b) One of the applications of the surface tension is the <u>capillarity</u> this is a property of liquids that depends on their surface tension (which, in turn, depends on the cohesion or intermolecular force of the liquid), which gives them the ability to climb or descend through a capillary tube.

Other examples of surface tension:

The mosquitoes that can sit on the water.

A clip on the water.

Some leaves that remain floating on the surface.

Some soaps and detergents on the water.

5 0
3 years ago
The work done by an external force to move a -8.50 μC charge from point a to point b is 6.10×10−4 J . If the charge was started
bekas [8.4K]

Answer:

-54.12 V

Explanation:

The work done by this force is equal to the difference between the final value and the initial value of the energy. Since the charge starts from the rest its initial kinetic energy is zero.

W=\Delta E\\W=\Delta K+\Delta U\\W=K_f+\Delta U\\\Delta U=W-K_f\\\Delta U=6.10*10^{-4}J-1.50*10^{-4}J\\\Delta U=4.60*10^{-4}J

The change in electrostatic potential energy \Delta U, of one point charge q is defined as the product of the charge and the potential difference.

\Delta U=qV\\V=\frac{\Delta U}{q}\\V=\frac{4.60*10^{-4}J}{-8.50*10^{-6}C}\\V=-54.12 V

5 0
3 years ago
Two sounds are played for you. The first has a frequency of 196 Hz. The second has a frequency of 392 Hz. Which sound will be "h
kykrilka [37]

Answer:

The second one, the higher the hertz the higher the frequency we hear

Explanation:

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2 years ago
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