Lenses used in eyeglasses, whether converging or diverging, are always designed such that the middle of the lens curves away from the eye. Why?
> The undergraduate grade point average (GPA) for students accepted at a random sample of 10 medical schools in the United States was taken. The mean GPA for these accepted students was 3.75 with a standard error of 0.06. The distribution of undergraduate
> In a study published in The New England Journal of Medicine, researchers investigated the effectiveness of the drug pembrolizamab on increasing survival rates in patients with advanced melanoma (Eggermont et al. 2018). In this randomized double-blind stu
> Early exposure to complex dietary proteins may increase risk of Type 1 diabetes in children with genetic susceptibility to this disease. In a double-blind randomized clinical trial reported in JAMA infants identified to be genetically at risk for develop
> Handing over the care of a patient from one anesthesiologist to another occurs during some surgeries. A study was conducted to determine if this transfer of care might increase the risk of adverse outcomes (Jones et al. 2018). Read the excerpt from the s
> State whether each situation has independent or paired (dependent) samples. a. A researcher wants to know whether pulse rates of people go down after brief meditation. She collects the pulse rates of a random sample of people before meditation and then c
> An article in the British medical journal The Lancet claimed that autism was caused by the measles, mumps, and rubella (MMR) vaccine (Wakefield et al. 1998). This vaccine is typically given to children twice, at about the age of 1 and again at about 4 ye
> Researchers have found that psychological distance from our current situation facilitates selfcontrol and allows individuals to transcend urgencies of a situation by taking a more distanced perspective. Executive function refers to higher-order regulator
> Some researchers believe that dogs may be beneficial in reducing cardiovascular risk in their owners by providing social support and motivation for physical activity (Mubanga et al. 2017). The purpose of this study was to investigate the association of d
> The alumni office wishes to determine whether students who attend a reception with alumni just before graduation are more likely to donate money within the next two years. a. Describe a study based on a sample of students that would allow the alumni offi
> In a 2017 study published in the journal Food Quality and Preference, researchers investigated the effect of drinking tea on divergent creativity (Huang et al. 2017). Subjects were recruited from a campus Bulletin Board System and were paid a small stipe
> Sixty-six reading students were randomly assigned to be taught using one of three teaching methods. One method is called Basal and uses textbooks that are organized to develop reading skills. Another method is called DRTA (Directed Reading Thinking Activ
> A random sample of students was studied. Whether the student chose to sit in the front, middle, or back row in a college class was observed, along with the person’s GPA. Test the hypothesis that GPA is associated with row using a signif
> Jennifer Brogan, a biology student who was taking a statistics class, exposed similar tomato plants to different colors of light. The average growth rates (in millimeters per week) are given in the table. a. Interpret the boxplots given. Compare medians
> A 2018 Gallup poll asked respondents if they supported same-sex marriage. Results are reported by political party in the StatCrunch output that follows. a. Find the percentage in each political party who support same-sex marriage. Round off to one decima
> The Perry Preschool Project data presented in exercise 10.39 can be divided to see whether there are different effects for males and females. The table shows a summary of the data for males (Schweinhart et al. 2005). a. Find the graduation rate for males
> A 95% confidence interval for the ages of the first six presidents at their inaugurations is (56.2, 59.5). Either interpret the interval or explain why it should not be interpreted.
> The Perry Preschool Project data presented in exercise 10.39 (Schweinhart et al. 2005) can be divided to see whether the preschool attendance effect is different for males and females. The table shows a summary of the data for females, and the figure sho
> The Perry Preschool Project was created in the early 1960s by David Weikart in Ypsilanti, Michigan. One hundred twenty three African American children were randomly assigned to one of two groups: One group enrolled in the Perry Preschool, and one did not
> Randomly chosen people were observed for about 10 seconds in several public places, such as malls and restaurants, to see whether they smiled during that time. The table shows the results for different age groups. (Source: M. S. Chapell, Frequency of Pub
> The table shows the results of a two-way table of gender and whether a person is happy in his or her marriage, according to data obtained from a General Social Survey. Happiness of Marriage X Respondent’s Sex Cross Tabulation Count a. I
> The weights of four randomly and independently selected bags of tomatoes labeled 5 pounds were found to be 5.1, 5.0, 5.3, and 5.1 pounds. Assume Normality. a. Find a 95% confidence interval for the mean weight of all bags of tomatoes. b. Does the interva
> Why do we calculate s by dividing by n - 1, rather than just n? The reason is that if we divide by n - 1, then s2 is an unbiased estimator of s2, the population variance. We want to show that s2 is an unbiased estimator of s2, sigma squared. The mathemat
> The following table shows the heights (in inches) of a random sample of students and their parent of the same gender. Test the hypothesis that the mean for the students is more than the mean for the parents, at the 0.05 level. Assume the data are Normal.
> The table shows the prices for identical groceries at two online grocery delivery services, Amazon and Walmart. Assume the sampling is random and the populations are Normal. a. Give the data, would a two-sample t-test or a paired t-test be appropriate to
> Data were collected on the weights of random samples of professional hockey players and professional baseball players. (Source: NHL.com, MLB.com) a. Using these descriptive statistics, can a two sample t-test be used to determine if there is a difference
> Data were collected on calorie content for a random sample of ales and lagers and are summarized in the table. Assume the conditions for using a t-test are satisfied. (Source: efficientdrinker.com) a. If we wanted to use a hypothesis test to determine if
> Suppose that 200 statistics students each took a random sample (with replacement) of 50 students at their college and recorded the ages of the students in their sample. Then each student used his or her data to calculate a 95% confidence interval for the
> Reaction distances in centimeters for a random sample of 40 college students were obtained. Shorter distances indicate quicker reactions. Each student tried catching a meter stick with his or her dominant hand and nondominant hand. The subjects all start
> The number of hours per week of television viewing for random samples of fifth-grade boys and fifth-grade girls were obtained. Each student logged his or her hours for one Monday-through-Friday period. Assume that the students were independent; for examp
> The final exam grades for a sample of daytime statistics students and evening statistics students at one college are reported. The classes had the same instructor, covered the same material, and had similar exams. Using graphical and numerical summaries,
> Elena Lucin, a statistics student, collected the data in the table showing heart rate (beats per minute) for a random sample of coffee drinkers before and 15 minutes after they drank coffee. Carry out a complete analysis, using the techniques you learned
> The weights of four randomly and independently selected bags of potatoes labeled 20 pounds were found to be 21.0, 21.5, 20.5, and 21.2 pounds. Assume Normality. a. Find a 95% confidence interval for the mean weight of all bags of potatoes. b. Does the in
> Brain size for 20 random women and 20 random men was obtained and is reported in the table (in hundreds of thousands of pixels shown in an MRI). Test the hypothesis that men tend to have larger brains than women at the 0.05 level. (Source: Willerman, L.,
> A fast-food chain advertises that the medium size serving of French fries weighs 135 grams. A reporter took a random sample of 10 medium orders of French fries and weighed each order. The weights (in grams) were 111, 124, 125, 156, 127, 134, 135, 136, 13
> A McDonald’s fact sheet says its cones should weigh 3.18 ounces (converted from grams). Suppose you take a random sample of four cones, and the weights are 4.2, 3.4, 3.9, and 4.4 ounces. Assume that the population distribution is Normal, and, for all thr
> In the study referenced in exercise 10.33, researchers also collected data on use of apps to monitor diet and calorie intake. The data are reported in the table. Test the hypothesis that diet app use and gender are associated. Use a 0.05 significance lev
> In a 2015 study reported in the Journal of American College Health, Cho et al. surveyed college students on their use of apps to monitor their exercise and fitness. The data are reported in the table. Test the hypothesis that fitness app use and gender a
> Use the data given in exercise 11.35. Follow the instructions given in exercise 11.43.
> Suppose that a new nicotine patch to help people quit smoking was developed and tested. Smokers voluntarily entered the study and were randomly assigned either the nicotine patch or a placebo patch. Suppose that a larger percentage of those using the nic
> A dedicated sports car enthusiast polishes the inside and outside surfaces of a hubcap that is a section of a sphere. When he looks into one side of the hubcap, he sees an image of his face 30.0 cm in back of it. He then turns the hubcap over, keeping it
> A 2.00 - cm - high object is placed 3.00 cm in front of a concave mirror. If the image is 5.00 cm high and virtual, what is the focal length of the mirror?
> While looking at her image in a cosmetic mirror, Dina notes that her face is highly magnified when she is close to the mirror, but as she backs away from the mirror, her image first becomes blurry, then disappears when she is about 30 cm from the mirror,
> (a) Does your bathroom mirror show you older or younger than your actual age? (b) Compute an order - of - magnitude estimate for the age difference, based on data you specify.
> The index of refraction for violet light in silica flint glass is 1.66 and that for red light is 1.62. What is the angular dispersion of visible light passing through an equilateral prism of apex angle 60.0° if the angle of incidence is 50.0&A
> A person swimming underwater on a bright day and looking up at the surface will see a bright circle surrounded by relative darkness as in Figure P22.61a, a phenomenon known as Snell’s window. Use the concept of total internal reflection
> Three sheets of plastic have unknown indices of refraction. Sheet 1 is placed on top of sheet 2, and a laser beam is directed onto the sheets from above so that it strikes the interface at an angle of 26.5° with the normal. The refracted beam in sheet 2
> Figure P22.59 shows the path of a beam of light through several layers with different indices of refraction. (a) If θ1 5 30.0°, what is the angle θ2 of the emerging beam? (b) What must the incident angle θ
> Students allow a narrow beam of laser light to strike a water surface. They arrange to measure the angle of refraction for selected angles of incidence and record the data shown in the following table: Angle of Incidence (degrees) …………… Angle of Refracti
> A light ray enters a rectangular block of plastic at an angle θ1 = 45.0° and emerges at an angle θ2 5 76.0°, as shown in Figure P22.57. (a) Determine the index of refraction of the plastic. (b) If the light
> A laser beam strikes one end of a slab of material, as in Figure P22.56. The index of refraction of the slab is 1.48. Determine the number of internal reflections of the beam before it emerges from the opposite end of the slab. Figure P22.56:
> A transparent cylinder of radius R = 2.00 m has a mirrored surface on its right half, as shown in Figure P22.55. A light ray traveling in air is incident on the left side of the cylinder. The incident light ray and the exiting light ray are parallel, and
> A light ray traveling in air is incident on one face of a right-angle prism with index of refraction n = 1.50, as shown in Figure P22.54, and the ray follows the path shown in the figure. Assuming θ = 60.0° and the base of the pri
> A piece of wire is bent through an angle θ. The bent wire is partially submerged in benzene (index of refraction = 1.50) so that, to a person looking along the dry part, the wire appears to be straight and makes an angle of 30.0° with the horizontal. Det
> Endoscopes are medical instruments used to examine the gastrointestinal tract and other cavities inside the body. The light required for examination is conducted from an outside source along a long, flexible bundle of optical fibers to the tip, where it
> One technique for measuring the angle of a prism is shown in Figure P22.51. A parallel beam of light is directed onto the apex of the prism so that the beam reflects from opposite faces of the prism. Show that the angular separation of the two reflected
> A narrow beam of light is incident from air onto a glass surface with index of refraction 1.56. Find the angle of incidence for which the corresponding angle of refraction is one-half the angle of incidence. Hint: You might want to use the trigonometric
> Refraction causes objects submerged in water to appear less deep than they actually are. The fish in Figure P22.49 has an apparent depth of 1.25 m. Calculate its actual depth. Figure P22.49:
> A light ray of wavelength 589 nm is incident at an angle θ on the top surface of a block of polystyrene surrounded by air, as shown in Figure P22.48. (a) Find the maximum value of θ for which the refracted ray will undergo total
> When a man stands near the edge of an empty drainage ditch of depth 2.80 m, he can barely see the boundary between the opposite wall and bottom of the ditch as in Figure P22.47a. The distance from his eyes to the ground is 1.85 m. (a) What is the horizon
> The level of water in a clear, colorless glass can easily be observed with the naked eye. The level of liquid helium in a clear glass vessel is extremely difficult to see with the naked eye. Explain. Hint: The index of refraction of liquid helium is clos
> A ray of light is incident at an angle 30.0° on a plane slab of flint glass surrounded by water. (a) Find the refraction angle. (b) Suppose the index of refraction of the surrounding medium can be adjusted, but the incident angle of the light remains the
> A layer of ice having parallel sides floats on water. If light is incident on the upper surface of the ice at an angle of incidence of 30.0°, what is the angle of refraction in the water?
> A boy floating on a pond watches a fish swim away from him as in Figure P22.44. If the fish is 2.25 m beneath the surface, for what maximum distance d will he be able to see the fish? Neglect the height of the boy’s eyes above the water
> The U.S. Food and Drug Administration limits the radiation leakage of microwave ovens to no more than 5.0 mW/cm2 at a distance of 2.0 in. A typical cell phone, which also transmits microwaves, has a peak output power of about 2.0 W. (a) Approximating the
> One possible means of achieving space flight is to place a perfectly reflecting aluminized sheet into Earth’s orbit and to use the light from the Sun to push this solar sail. Suppose such a sail, of area 6.00 x 104 m2 and mass 6.00 x 103 kg, is placed in
> A particular inductor has appreciable resistance. When the inductor is connected to a 12 - V battery, the current in the inductor is 3.0 A. When it is connected to an AC source with an rms output of 12 V and a frequency of 60. Hz, the current drops to 2.
> A dish antenna with a diameter of 20.0 m receives (at normal incidence) a radio signal from a distant source, as shown in Figure P21.73. The radio signal is a continuous sinusoidal wave with amplitude Emax = 0.20 μV/m. Assume the antenna ab
> (a) What capacitance will resonate with a one - turn loop of inductance 400. pH to give a radar wave of wavelength 3.0 cm? (b) If the capacitor has square parallel plates separated by 1.0 mm of air, what should the edge length of the plates be? (c) What
> As a way of determining the inductance of a coil used in a research project, a student first connects the coil to a 12.0 - V battery and measures a current of 0.630 A. The student then connects the coil to a 24.0 - V (rms), 60.0 - Hz generator and measur
> In an RLC series circuit that includes a source of alternating current operating at fixed frequency and voltage, the resistance R is equal to the inductive reactance. If the plate separation of the parallel - plate capacitor is reduced to one - half its
> A virtual image is often described as an image through which light rays don’t actually travel, as they do for a real image. Can a virtual image be photographed?
> A 200. - Ω resistor is connected in series with a 5.0 - μF capacitor and a 60 - Hz, 120 - V rms line. If electrical energy costs $0.080/ kWh, how much does it cost to leave this circuit connected for 24 h?
> The intensity of solar radiation at the top of Earth’s atmosphere is 1370 W/m3. Assuming 60% of the incoming solar energy reaches Earth’s surface and assuming you absorb 50% of the incident energy, make an order - of - magnitude estimate of the amount of
> A 25.0 - mW laser beam of diameter 2.00 mm is reflected at normal incidence by a perfectly reflecting mirror. Calculate the radiation pressure on the mirror.
> A speeder tries to explain to the police that the yellow warning lights she was approaching on the side of the road looked green to her because of the Doppler shift. How fast would she have been traveling if yellow light of wavelength 580 nm had been shi
> Police radar guns measure the speed of moving vehicles by transmitting electromagnetic waves at a vehicle and detecting a Doppler shift in the reflected wave. Suppose police radar transmits at a frequency of 24.0 GHz and receives a wave reflected from a
> A spaceship is approaching a space station at a speed of 1.8 x 105 m/s. The space station has a beacon that emits green light with a frequency of 6.0 x 1014 Hz. (a) What is the frequency of the beacon observed on the spaceship? (b) What is the change in
> The rainbow of visible colors in the electromagnetic spectrum varies continuously from the longest wavelengths (the reddest colors) to the shortest wavelengths (the deepest violet colors) our eyes can detect. Wavelengths near 655 nm are perceived as red.
> An important news announcement is transmitted by radio waves to people who are 100. km away, sitting next to their radios, and by sound waves to people sitting across the newsroom, 3.0 m from the newscaster. Who receives the news first? Explain. Take the
> What are the wavelength ranges in (a) The AM radio band (540–1600 kHz) and (b) The FM radio band (88–108 MHz)?
> A diathermy machine, used in physiotherapy, generates electromagnetic radiation that gives the effect of “deep heat” when absorbed in tissue. One assigned frequency for diathermy is 27.33 MHz. What is the wavelength of this radiation?
> A type of mirage called a pingo is often observed in Alaska. Pingos occur when the light from a small hill passes to an observer by a path that takes the light over a body of water warmer than the air. What is seen is the hill and an inverted image direc
> What are the wavelengths of electromagnetic waves in free space that have frequencies of (a) 5.00 x 1019 Hz and (b) 4.00 x 109 Hz?
> Consider a bright star in our night sky. Assume its distance from the Earth is 20.0 light - years (ly) and its power output is 4.00 x 1028 W, about 100 times that of the Sun. (a) Find the intensity of the starlight at the Earth. (b) Find the power of the
> A microwave oven is powered by an electron tube called a magnetron that generates electromagnetic waves of frequency 2.45 GHz. The microwaves enter the oven and are reflected by the walls. The standing - wave pattern produced in the oven can cook food un
> A laser beam is used to levitate a metal disk against the force of Earth’s gravity. (a) Derive an equation giving the required intensity of light, I, in terms of the mass m of the disk, the gravitational acceleration g, the speed of light c, and the cros
> The Sun delivers an average power of 1370. W/m2 to the top of Earth’s atmosphere. Find the magnitudes of E(max and B(max for the electromagnetic waves at the top of the atmosphere.
> The transmission of light energy as it passes through a solution of light - absorbing molecules is described by the Beer–Lambert law which gives the decrease in intensity I in terms of the distance L the light has traveled through a fl
> Oxygenated hemoglobin absorbs weakly in the red (hence its red color) and strongly in the near infrared, whereas deoxygenated hemoglobin has the opposite absorption. This fact is used in a “pulse oximeter” to measure oxygen saturation in arterial blood.
> The speed of light in vacuum is defined to be c = 299792458 m/s = 1/√μ0є0. The permeability constant of vacuum is defined to be μ0 = 4π x 10-7 N · s2/C2. Use these definitions to calculate the value of є0, the permittivity of free space, to eight signifi
> The Earth reflects approximately 38.0% of the incident sunlight from its clouds and surface. (a) Given that the intensity of solar radiation at the top of the atmosphere is 1370 W/m2, find the radiation pressure on the Earth, in pascals, at the location
> (a) The distance to Polaris, the North Star, is approximately 6.44 x 1018 m. If Polaris were to burn out today, how many years would it take to see it disappear? (b) How long does it take sunlight to reach Earth? (c) How long does it take a microwave sig
> Construct ray diagrams to determine whether each of the following statements is true (T) or false (F). (a) For an object at a concave mirror’s center of curvature, the image is real and inverted. (b) As an object approaches the focal point of a concave m
> The U.S. Navy has long proposed the construction of extremely low frequency (ELF waves) communications systems; such waves could penetrate the oceans to reach distant submarines. Calculate the length of a quarter - wavelength antenna for a transmitter ge
> A transmission line that has a resistance per unit length of 4.50 x 10-4 Ω/m is to be used to transmit 5.00 MW over 400 miles (6.44 x 105 m). The output voltage of the generator is 4.50 kV (rms). (a) What is the line loss if a transformer is used to step
> A transformer on a pole near a factory steps the voltage down from 3600 V (rms) to 120 V (rms). The transformer is to deliver 1.0 x 103 kW to the factory at 90% efficiency. Find (a) The power delivered to the primary, (b) The current in the primary, and
> An ideal neon sign transformer provides 9250 V at 30.0 mA with an input voltage of 115 V. Calculate the transformer’s input (a) Power and (b) Current.
> An AC power generator produces 50. A (rms) at 3600 V. The voltage is stepped up to 1.0 x 105 V by an ideal transformer, and the energy is transmitted through a long - distance power line that has a resistance of 100. Ω. What percentage of the power deliv
> A step - down transformer is used for recharging the batteries of portable devices. The turns ratio N2/N1 for a particular transformer used in a CD player is 1:13. When used with 120. - V (rms) household service, the transformer draws an rms current of 2
> The light beam in Figure P22.43 strikes surface 2 at the critical angle. Determine the angle of incidence, θ1. Figure P22.43:
