A survey of 700 high school students in our stat showed that 216 felt unsafe in their local school. Construct a 95% confidence interval for the proportion of students who felt unsafe.

The grades on an examination are normally distributed with mean of 400 and standard deviation of 40. If a sample 25 students is randomly selected, what is the probability that the average score of these 25 students is above 405?

For doing a survey for meal plan evaluation, discuss how do you choose 100 samples for a university with 20,000 students, in which there are 15,000 native American and 5,000 foreigner students

Test at α =.05 the hypothesis that a majority (more than 50%) of students favor the plus/minus grading system at a university if in a random sample of 400 students, 216 favor the system?

What are some things you like to do to keep your students motivated to want to learn? Or what will you do to turn a negative thought into a positive thought in your students?

Do you have any experience in your own classrooms using creative arts to assess students in ELA? For instance, students may draw pictures of their favorite character in a book?

Part A

Find the energy U0 stored in the capacitor. Express your answer in terms of A, d, V, and ϵ0. Remember to enter ϵ0 as epsilon0.

Part B

The capacitor is now disconnected from the battery, and the plates of the capacitor are then slowly pulled apart until the separation reaches 3d. Find the new energy U1 of the capacitor after this process.

Express your answer in terms of A, d, V, and ϵ0.

Part C

The capacitor is now reconnected to the battery, and the plate separation is restored to d. A dielectric plate is slowly moved into the capacitor until the entire space between the plates is filled. Find the energy U2 of the dielectric-filled capacitor. The capacitor remains connected to the battery. The dielectric constant is K.

Express your answer in terms of A, d, V, K, and ϵ0.

A 580-mm long tungsten wire, with a 0.046-mm-diameter circular cross section, is wrapped around in the shape of a coil and used as a filament in an incandescent light bulb. When the light bulb is connected to a battery, a current of 0.526 A is measured through the filament. (Note: tungsten has a resistivity of 4.9 × 10-8 ? • m.) How many electrons pass through this filament in 5 seconds?

How many electrons pass through this filament in 5 seconds? 4.22 × 10-19 2.63 3.29 × 1018 1.64 × 1019

What is the resistance of this filament? What is the resistance of this filament? 4.28 ? 58.5 m? 17.1 ? 9.0 ?

What is the voltage of the battery that would produce this current in the filament? 31 mV 9.0 V 2.6 × 10-8 V 32 V

This is an astronomy question:

Two stars, both with surface temperatures of 9700 K, deposit 1000 photons/second and 3200 photons/second on our detector (of unit size), respectively, when observed with a V filter (visual).

(a) How do their V-band magnitudes compare (i.e. what is V1 - V2)?

(b) How do their B magnitudes compare?

Student's note: I'm deeply confused on how to even begin this. Please show work so I can understand this. It's not clear to me whether I'm supposed to do a calculation to determine V magnitudes and B magnitudes knowing only temp and flux or whether I'm supposed to be looking something up on a table somewhere. I just don't know where to start. Thank you

A phase transition from solid to liquid takes place at constant pressure and temperature. This is a closed PVT system. (a) Show that the Gibbs free energy G = U - TS + PV is a constant. (b) The solid and liquid phases are in equilibrium at a temperature T and pressure P, where G(solid) = G(solid)(T,P) and G(liquid) = G(liquid)(T,P). The phases are also in equilibrium at the neighboring temperature T +dT and pressure P + dP, where G(solid) = G(solid)(T+dT, P+dP) and G(liquid) = G(liquid)(T+dT, P+dP). Show that at temperature T, (dP/dT) = (S(liquid) - S(solid)) / (V(liquid) - V(solid)) where S and V denote entropy and volume respectively.