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Researchers wanted to determine if having a high-quality sound system in the bedroom is associated with obesity. The researchers administered a questionnaire to 305 twelve-year-old adolescents. After analyzing the results, the researchers determined that the body mass index of the adolescents who had a high-quality sound system in their bedroom was significantly higher than that of the adolescents who did not have a high-quality sound system in their bedroom. Complete parts (a) through (e) below. (a) Why is this an observational study? What type of observational study is this? Why is this an observational study? A. The researchers administered a questionnaire to obtain their data without trying to influence an explanatory variable of the study. B. The researchers observed the behavior of the individuals in the study without trying to influence an explanatory variable of the study. C. The researchers intentionally changed an explanatory variable of the study. D. The researchers tried to influence the outcome of the study.

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Consider a population consisting the scores of 6 students in a Statistic test. \[ 18,22,25,28,32,36 \] Suppose samples of size 3 are drawn from this population, describe the sampling distribution of the sample means following the steps below: 1. What is the mean of the population? Show your solutions here. 2. What is the variance of the population? Fill in the table and show your solutions here. \begin{tabular}{|l|l|l|} \hline$ X $ & $ (\boldsymbol{X}-\boldsymbol{\mu}) $ & $ (\boldsymbol{X}-\boldsymbol{\mu})^{2} $ \\ \hline & & \\ \hline & & \\ \hline & & \\ \hline & & \\ \hline & & \\ \hline & & \\ \hline \end{tabular} 3. Determine the number of possible samples of size 3 Show your solutions here. 25

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A building is purchased for £200,000 and leased for a period of eight years. Rent of £10,000 is charged annually at the end of the year. The rent charged increases by 5% every year following the first year. The building is expected to be sold for £250,000 at the end of Year 8. What is the cash outflow at the beginning of Year 1?

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The quantity (1/2) epsi _(0)E^(2) has the significance of ........ (a) energy/volume (b) energy/farad (c) energy/volt A wire with a length of 150m and a radius of 0.15mm carries a current with a uniform current density of 2.8 imes 10^(7)(A)/(m)2. The current is about (a) 29.63A (b) 2A (c) 0.54A A cable having radius 1mm in which 10A current pass. If 1m^(3) of the cable conducting material contains 5.8 imes 10^(28) free electrons. What is the drift velocity of electrons? (a) 43.3(m)/(s) (b) 0.343m(m)/(s) (c) 2.6(m)/(s) What is the radius of a copper wire needed for keeping the resistance at 0.4Omega , if the wire length is 20m. Assuming the resistivity at 20deg C is 1.68 imes 10^(-8)Omega .m ? (a) 0.85mm (b) 1.30mm (c) 0.51mm In the previous problem, if copper's temperature coefficient is 4.3 imes 10^(-3)K^(-1), what would be the value of the resistivity if the temperature is raised from 20deg C to 420 deg C ? (a) 4.56 imes 10^(-8)Omega .m (b) 7.53 imes 10^(-8)Omega .m (c) 9.45 imes 10^(-8)Omega .m A certain wire has resistance R. Another wire, of the same material, has half the length and half the diameter of the first wire. The resistance of the second wire is: (a) (R)/(4) (b) (R)/(2) (c) 2R A wire is 1m long and has cross-sectional area 1 imes 10^(-6)m^(2). When connected to a potential difference of 2V, a current of 4A exists in the wire. The resistivity of this wire is ......... (a) 5 imes 10^(-7)Omega *m (b) 2 imes 10^(-6)Omega *m (c) 4 imes 10^(-5)Omega *m Physical Constants: e=1.6 imes 10^(-19)C;k=8.99 imes 10^(9)N*(m^(2))/(C^(2)) epsi _(0)=8.85 imes 1^() -12(C^(2))/(N)*m^(2) 14. The quantity(1/2)go E has the significance of .. (a)energy/volume (b)energy/farad (c)energy/volt 15. A wire with a length of 150 m and a radius of 0.15 mm carries a current with a uniform current density of 2.8 x 107 A/m2.The current is about ... a29.63A b2A c0.54A 16. A cable having radius 1 mm in which 10 A current pass.If 1 m3 of the cable electrons? a43.3m/s (b) 0.343 mm/s (c) 2.6 m/s What is the radius of a copper wire needed for keeping the resistance at O.4 ,if the wire length is 20 m.Assuming the resistivity at 20 C is 1.68 x 10-8 .m? a)0.85 mm (b) 1.30 mm c0.51 mm 17. 18. In the previous problem, if copper's temperature coefficient is 4.3x10-3 K-1,what would be the value of the resistivity if the temperature is raised from 20 C to 420 C? a4.5610-.m (b7.5310-8Q.m (c)9.45 x 10-8 .m 19. A certain wire has resistance R.Another wire,of the same material,has half the length and half the diameter of the first wire. The resistance of the second wire is: (a) R/4 (b) R/2 (c) 2R 20. A wire is 1 m long and has cross-sectional area 1 x 10- m2.When connected to a potential difference of 2 V,a current of 4 A exists in the wire. The resistivity of this wire is. a510-7m (b)2 10-6 m (c) 4 x 10-5 m Physical Constants: e=1.6 10-19 C;k=8.99x 109 N.m2/C2 =8.85x10-12C2/N.m2

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Object p. ? 30cm 40cm Final image Exercise 5-1 A goldfish lives in a rectangular aquarium. The index of water n=1.33. If the fish is 10cm from the near edge of the aquarium, where does the fish appear when viewed from the outside? Fish's position 10cm Rectangular aquarium Fiewer Exercise 6-1 An anti-shoplifting mirror (see photo) shows an image of a woman who is located 3m from the mirror. The focal length of the mirror is -0.25m. Find a) the position of her image, b) the magnification of the image. Exercise 7-1 A goldfish lives in a spherical fish bowl 50cm diameter. The index of water n=1.33. If the fish is 10cm from the near edge of the bowl, where does the fish appear when viewed from the outside? Exercise 8-1 To see a flower better, a naturalist holds a 6cm focal length magnifying glass 4cm from the flower. What is the magnification? Exercise 9-1 A diverging lens with a focal length of 50cm is placed 100cm from a flower. a) Where is the image? b) What is the magnification? Exercise 10-1 2 A stamp collector uses a magnifying lens that sits 2cm above the stamp. The magnification is 4. What is the focal length of the lens? Exercise 11-1 A camera is usually a combination of two or more single lenses. Consider a camera lens consisting of a diverging lens, with $f_1$=120mm, and a converging lens, with $f_2$=42mm, spaced 60mm apart. A 10cm tall object is 500mm from the first lens. What are the location, size, and orientation of the image?

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Q3. Consider the system block diagram given below. The transfer function will have a quadratic polynomial denominator of the form $D(s) = s^2 + 2\zeta\omega_n s + \omega_n^2$ Find: 1) The transfer function of the system 2) The value of $k$ such that the damping ratio $\zeta = 0.5$. 3) The rise time $T_r$ to a unit step reference, where $T_r = \frac{\pi - \beta}{\omega_d}$, $\beta = cos^{-1}\zeta$, ($\beta$ in radians), and $\omega_d = \omega_n\sqrt{1 - \zeta^2}$. 4) The value of $k$ for a steady state error of 7% for a unit ramp input. 5) The velocity error constant $K_v$.

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10. Sketch the electric field for the diagram below. Calculate the electric field at the point indicated. \text{5 Coulombs} 1.4m 2m 1m Perfect Conductor

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Question 3 6 out of 6 points A thin, cylindrical rod $l = 25.0$ cm long with a mass $m = 1.20$ kg has a ball of diameter $d = 10.00$ cm and mass $M = 2.00$ kg attached to one end. The arrangement is originally vertical and stationary, with the ball at the top as shown in the figure below. The combination is free to pivot about the bottom end of the rod after being given a slight nudge. a) After the combination rotates through 90 degree, what is its rotational kinetic energy (in J)? Selected Answer: 7.35 Question 4 b)What is the angular speed of the rod and ball (in rad/s)? Selected Answer: 8.43 Question 5 c) What is the linear speed of the center of mass of the ball (in m/s)? Selected Answer: 2.62 4 out of 4 points 0 out of 5 points

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Finish writing a C program (in the space identified below) that determines the maximum and the minimum among three numbers entered by a user. The both maximum and minimum should be printed (displayed) at the end of the program. #include <stdio.h> int main (void) { /* these are definitions of variable yo should use in the program */ int no_1, no_2, no_3; int minimum; int maximum; /* code for entering three numbers */ printf("please, enter three numbers\n"); scanf("%d %d %d", &no_1, &no_2, &no_3); /* your code comes here */

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The responsibility for fiscal policy lies with: the President and Congress, together the President alone congress alone the Federal Reserve

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christopher c.