A professor tests whether the loudness of noise during an assignment (low, medium, and high) is independent of exam grades (pass, fail). The following table shows the observed frequencies for this test.

(a) Conduct a chi-square test for independence at a 0.05 level of significance. (Round your answer to two decimal places.)
=  

Decide whether to retain or reject the null hypothesis.

Retain the null hypothesis.Reject the null hypothesis.   

(b) Compute effect size using Cramer's V. (Round your answer to two decimal places.)
V =

(2:) Q: What can you do to make a parallel-plate capacitor larger? There are several things. Describe as many as you can.

In the RC circuit to the right, the capacitor C has a value of 10 LiF and the resistor is 144 kQ. The battery has an EMF of 16 V.
The circuit is assembled with capacitor is uncharged. At t = 0 s terminal A is cormected to terminal 8, causing the battery to charge the capacitor.

(i) What is the half-life (s) of this circuit? At the time of t = 0.54 s:

(ii) Calculate the voltage of the capacitor.
(iii) Calculate the voltage across the resistor.
(iv) Calculate the current flowing through the circuit. (v) Calculate the power being dissipated in the resistor.

Suppose that the S&P 500, with a beta of 1.0, has an expected return of 11% and T-bills provide a risk-free return of 6%.

a. What would be the expected return and beta of portfolios constructed from these two assets with weights in the S&P 500 of (i) 0; (ii) 0.25; (iii) 0.50; (iv) 0.75; (v) 1.0? (Leave no cells blank - be certain to enter "0" wherever required. Do not round intermediate calculations. Enter the value of Expected return as a percentage rounded to 2 decimal places and value of Beta rounded to 2 decimal places.)

A single- phase full- wave rectifier is used to control the speed of a 5- hp, 110- V, 1200- rpm, separately- excited dc motor. The converter is connected to a single- phase, 120- V, 60- Hz supply. The motor has a winding resistance of 0.4ohms and an inductance of 5 mH, and a voltage constant K=0.09V/rpm.

a. During the motoring operation, the motor runs at 1000 rpm and receives an armature current of 30 A. Determine the corresponding firing angle and the power to the motor.

b. The polarity of the emf is reversed to get a regenerative action. Determine the firing angle required to keep the motor speed at 1000 rpm with an armature current of 30A. What is the power fed back to the supply under these conditions?

1. Use Excel to plot x(t) versus time for 2 periods of the motion. Use the equations from
the lecture notes that are from the book. Put this in an Excel sheet call x_t

x(t) = A cos(ωt)

2. Use Excel to plot v(t) versus time for 2 periods of the motion. Use the equations from
the lecture notes that are from the book. Put this in an Excel sheet call v_t

v(t) = -ωAsin(ωt)

3. Use Excel to plot a(t) in m/s2 versus time for 2 periods of the motion. Use the equations
from the lecture notes that are from the book. . Put this in an Excel sheet call a_t

a(t) = -ω2Acos(ωt)

A psychologist studying addiction tests whether cravings for cocaine and relapse are independent. The following table lists the observed frequencies in the small sample of people who use drugs.

(a) Conduct a chi-square test for independence at a 0.05 level of significance. (Round your answer to two decimal places.)
=

(b) Compute effect size using ϕ and Cramer's V. Hint: Both should give the same estimate of effect size. (If necessary, round your intermediate steps to two or more decimal places. Round your answers to two decimal places.)

The potential barrier is defined by V(x) = ((A^2-(x^2)*(b^2))^0.5  where x is less than or equal to A/b.

First we want to sketch V(x)

Then we run a particle into it wth mass m and energy E (which is less than A). Now that we have run the particle into it we are asked to derive an expression for the probability of penetration in terms of D = E/A and sin (y) = bx/A.

Finally, we are to evaluate our expression in numerically for D=0.1 to 1.0 in steps of 0.1 for an electron stricking such a barrier with A=10 eV and b=2eV/angstrom.

Help!! I have no idea how to start this monster. How do I sketch this??

A covid-19 test manufacturer is testing its newest instant test. It tests a total of 500 people, 100 of whom are known to be have the virus. The following table shows the results:

1. Find the probability that a person has the virus but tests negative.
2. Find the probability that a person who has the virus tests negative.
3. Find the probability that a person who tests negative has the virus.
4. An acquaintance of yours has a negative test result. What is the probability that she does not have the virus?

4. The heart of the original Apple iPad is the Apple A4 chip which operates at 1.0 GHz and is believed to utilize ARM Cortex-A8 CPUs built with Samsung 45nm technology. Assume it dissipates 5 watts using a 1.1 V power supply.

a) If a prototype made in 65 nm is available, what speed and power consumption will the chip likely have assuming constant-field scaling?

b) If the supply voltage on the 65 nm part were scaled to 0.7 V, what will the power consumption and speed be then?

c) i) What supply voltage should be used by the 45 nm part to set the power consumption of 2.5 Watts?

ii) At what speed would the processor then operate?