A researcher wants to evaluate the effectiveness of cognitive behavior therapy which he thinks will decrease depression scores. Prior to testing, each of n = 10 patients rated their current level of depression on a self-report survey. After attending cognitive behavior therapy for a month, a second rating is recorded. The data are as follows:

           Before   After

                                                5          2

                                                7          7

                                                10         7

                                                14         10

Do the results indicate a significant difference? Use α = .01. If so, what percent of the decrease is actually due to the therapy?

company D is currently an unlevered firm. the company expects to generate $200 milllion of operating profits in perpetuity. the firm is considering a capital restructuring to have $500 million of debt. its cost of debt is 6%. unlevered firms in the same industry have cost of equity capital of 12%. the corporate tax rate is 30%. a. what is the value of company D before capital restructuring? b. what will be the value of company D after capital restructuring? c. what will be the WACC of company D after capital restructuring?

Loaded-up Fund charges a 12b-1 fee of 1% and maintains an expense ratio of 0.90%. Economy Fund charges a front-end load of 2%, but has no 12b-1 fee and an expense ratio of 0.10%. Assume the ratio of return on both funds' portfolios (before any fees) is 5% per year.

How much will an investment of $100 in each fund grow after 1 year?

How much will an investment of $100 in each fund grow after 2 years?

loaded-up fund

economy fund

How much will an investment of $100 in each fund grow after 9 years?

loaded-up fund

economy fund

USE PYTHON TO SOLVE THIS PROBLEM

A bacteria culture grows exponentially. After 2 hours, the bacteria count was 400 cells and after 6 hours, the bacteria count was 20,000 cells.

a) Solve a system of equations to find (approximately) k and y0 (HINT: If will help to assume K is real in the symbols command)

b) Use this to determine when the bacteria count reaches 2,000,000 (exact and approximate).

c) Suppose 400 was the “initial” amount and 20,000 the count after 4 hours. Find k and the approximate amount of bacteria 2 hour BEFORE the “initial” time. In a print statement, explain what you notice when comparing these answers to part a)

USE PYTHON TO SOLVE THIS PROBLEM

A bacteria culture grows exponentially. After 2 hours, the bacteria count was 400 cells and after 6 hours, the bacteria count was 10,000 cells.

a) Solve a system of equations to find (approximately) k and y0 (HINT: If will help to assume K is real in the symbols command)

b) Use this to determine when the bacteria count reaches 1,000,000 (exact and approximate).

c) Suppose 400 was the “initial” amount and 10,000 the count after 4 hours. Find k and the approximate amount of bacteria 2 hour BEFORE the “initial” time. In a print statement, explain what you notice when comparing these answers to part a)

*Use Python 3.7*

1. During a titration, it took 35.8mL of 0.10 M Be(OH)₂ to neutralize 65mL of HCl.

1. Write the balanced chemical reaction.
2. How many moles of beryllium hydroxide are needed to neutralize 2 moles of HCl?
3. What is the molarity of the HCl solution?

2. Consider a titration of 0.15M NaOH and 250 mL of 0.10M HBr.

1. What is the pH of the HBr solution before any base is added?
2. What is the pH after 50 mL NaOH is added?
3. What is the pH after 125 mL NaOH is added?
4. What is the pH after 150 mL NaOH is added?
5. Sketch the titration curve. Label the equivalence point on the graph and label the pH value at that point.

((8.27)Q:7)

Two ice skaters, Daniel (mass 70.0 kg ) and Rebecca (mass 45.0 kg ), are practicing. Daniel stops to tie his shoelace and, while at rest, is struck by Rebecca, who is moving at 14.0 m/s before she collides with him. After the collision, Rebecca has a velocity of magnitude 8.00 m/s at an angle of 55.1 ∘ from her initial direction. Both skaters move on the frictionless, horizontal surface of the rink.

A) What is the magnitude of Daniel's velocity after the collision?

B) What is the direction of Daniel's velocity after the collision?

C) What is the change in total kinetic energy of the two skaters as a result of the collision?

A block weighing 259 g slides along a frictionless track at a speed 6.1 cm/s. It then attaches to a spring-bumper with an electromagnetic device so that the block attaches to the bumper. The bumper has a mass of 130 g, and the spring has a stiffness of 1540 kg/s² and an equilibrium length of 10.6 cm. After the spring compresses and returns to its original length, the magnet turns off and the block launches off again, conserving energy.

(a) How fast is the block just after it attaches to the paddle?


(b) What is the maximum compression of the spring before the block turns around?


(b) How fast is the block moving after it launches off the paddle?