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 office to conclude that attending the reception causes future donations but that it is not possible to generalize this result to all students. b. Describe a study based on a sample of students that does not allow fundraisers to conclude that attending receptions causes future donations but does allow them to generalize to all students. c. Describe a study based on a sample of students that allows fundraisers to conclude that attending the reception causes future donations and also allows them to generalize to all students.
> Triglycerides are a form of fat found in the body. Using data from NHANES, we looked at whether men have higher triglyceride levels than women. a. Report the sample means, and state which group had the higher sample mean triglyceride level. Refer to the
> In exercise 9.63 you could not reject the null hypothesis that the mean salary for the two leagues are the same, using a two-tailed test with a significance level of 0.05. a. If you found a 95% confidence interval for the difference between means, would
> Using data from NHANES, we looked at the pulse rates of nearly 800 people to see whether men or women tended to have higher pulse rates. Refer to the Minitab output provided. a. Report the sample means, and state which group had the higher sample mean pu
> The table shows the Minitab output for a two-sample t-test for the number of televisions owned in households of random samples of students at two different community colleges. Each individual was randomly chosen independently of the others; the students
> Using data from NHANES, we looked at the pulse rate for nearly 800 people to see whether it is plausible that men and women have the same population mean. NHANES data are random and independent. Minitab output follows. a. Are the conditions for using a c
> Minitab output is shown for a two-sample t-interval for the number of televisions owned in households of random samples of students at two different community colleges. Each individual was randomly chosen independently of the others. One of the schools i
> A random sample of 10 independent healthy people showed the following body temperatures (in degrees Fahrenheit): 98.5, 98.2 99.0, 96.3, 98.3, 98.7, 97.2, 99.1, 98.7, 97.2 Test the hypothesis that the population mean is not 98.6 °F, using a significance l
> A StatCrunch survey asked respondents how much time they spent daily on various social media sites. Is there a difference in the mean time spent on these social media sites? Use the following ANOVA output. Do a complete ANOVA analysis with a significance
> Following the large-scale nuclear power plant failure in Japan, a StatCrunch survey was conducted in which respondents were asked about their level of concern over nuclear power and their political party. The data were coded so that 1 represented the low
> Use the data given in exercise 11.36. Follow the instructions given in exercise 11.43. Data from 11.36:
> Use the Minitab output (at the bottom of the page) showing the Tukey HSD post hoc analysis for exercise 11.31 to order the mean rents for these three cities from least expensive to most expensive.
> Use the data given in exercise 11.32. Follow the instructions given in exercise 11.43. Data from 11.32:
> Report and interpret the 95% confidence interval for the difference in mean systolic blood pressure for men and women (refer to the Minitab output in exercise 9.60). Does this support the hypothesis that men and women differ in mean systolic blood pressu
> Refer to exercise 11.38 to find the data. Follow the instructions given in exercise 11.43. Data from 11.38:
> 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 recorded, along with the person’s grade point average (GPA). Test the hypothesis that GPA is associated w
> Tukey HSD confidence intervals (with an overall significance level of 0.05) were calculated for the mean housing prices in three southern California neighborhoods: Agoura, Ventura, and Oxnard. The sample mean was largest for Agoura and smallest for Ventu
> A random sample of nurses working night shifts were asked whether they were fatigued (no or yes) and what form of sleep aid they used. Assume that each person used one sleep aid. The table shows the results. a. Why is a chi-square test for independence i
> In a 2016 article published in the Journal of American College Health, Heller et al. surveyed a sample of students at an urban community college. Students’ ages and frequency of alcohol use per month are recorded in the following table.
> In the study described in exercise 10.55, researchers (Du Toits et al., 2015) also studied infants with eczema, egg allergies, or both who also had a preexisting sensitivity to peanut extract. These infants were also randomly assigned to either consume o
> In a 2015 study reported in the New England Journal of Medicine, Du Toit et al. randomly assigned infants who were likely to develop a peanut allergy (as measured by having eczema, egg allergies, or both) to either consume or avoid peanuts until 60 month
> Rats had a choice of freeing another rat or eating chocolate by themselves. Most of the rats freed the other rat and then shared the chocolate with it. The table shows the data concerning the gender of the rat in control. a. Can a chi-square test for hom
> In a 2009 study reported in the New England Journal of Medicine, Boyer et al. randomly assigned children aged 6 months to 18 years who had nonlethal scorpion stings to receive an experimental antivenom or a placebo. “Goodâ€&#
> The data in the table come from a General Social Survey. The top row is the number of children reported for the respondents. The respondents also reported their level of happiness; Very H means Very Happy, and so on. The counts are shown in the table. Is
> Report and interpret the 95% confidence interval for the difference in mean triglyceride levels for men and women (refer to the Minitab output in exercise 9.59). Does this support the hypothesis that men and women differ in mean triglyceride level? Expla
> The data in the table are from a General Social Survey and concern gender and political party. a. Find the expected counts and report the smallest. Could we use the table as is, without combining categories? b. Create a new table, using the data from the
> The following numbers are the differences in pulse rate (beats per minute) before and after running for 12 randomly selected people. 24, 12, 14, 12, 16, 10, 0, 4, 13, 42, 4, and 16 Positive numbers mean the pulse rate went up. Test the hypothesis that th
> Ten people went on an Atkins diet for a month. The weight losses experienced (in pounds) were 3, 8, 10, 0, 4, 6, 6, 4, 2, and -2 The negative weight loss is a weight gain. Test the hypothesis that the mean weight loss was more than 0, using a significanc
> According to Statista.com, the average price of a ticket to a Broadway show in 2017 was $109.21. A random sample of 25 Broadway ticket prices in 2018 had a sample mean of $114.7 with a standard deviation of $43.3. a. Do we have evidence that Broadway tic
> According to Deadline.com, the average price for a movie ticket in 2018 was $8.97. A random sample of movie prices in the San Francisco Bay Area 25 movie ticket prices had a sample mean of $12.27 with a standard deviation of $3.36. a. Do we have evidence
> In the 2015 AFC Championship game, there was a charge the New England Patriots deflated their footballs for an advantage. The Patriots’ opponents during the championship game were the Indianapolis Colts. Measurements of the Colts footballs were taken. Th
> In the 2015 AFC Championship game, there was a charge the New England Patriots deflated their footballs for an advantage. The balls should be inflated to between 12.5 and 13.5 pounds per square inch. The measurements were 11.50, 10.85, 11.15, 10.70, 11.1
> In the United States, the population mean height for 10-year-old girls is 54.5 inches. Suppose a random sample of 15 10-year-old girls from Brazil is taken and that these girls had a sample mean height of 53.2 inches with a standard deviation of 2.5 inch
> In the United States, the population mean height for 3-year-old boys is 38 inches (http://www.kidsgrowth .com). Suppose a random sample of 15 non-U.S. 3-year-old boys showed a sample mean of 37.2 inches with a standard deviation of 3 inches. The boys wer
> A body mass index (BMI) of more than 25 is considered unhealthy. The Minitab output given is from 50 randomly and independently selected people from the NHANES study. Test the hypothesis that the mean BMI is more than 25 using a significance level of 0.0
> State whether each situation has independent or paired (dependent) samples. a. A researcher wants to compare food prices at two grocery stores. She purchases 20 items at Store A and finds the mean and the standard deviation for the cost of the items. She
> In the U.S. Department of Health has suggested that a healthy total cholesterol measurement should be 200 mg/dL or less. Records from 50 randomly and independently selected people from the NHANES study showed the results in the Minitab output given: Test
> Use the data from exercise 9.36. a. Using the four-step procedure with a two-sided alternative hypothesis, should you be able to reject the hypothesis that the population mean is 5 pounds using a significance level of 0.05? Why or why not? The confidence
> Use the data from exercise 9.35. a. If you use the four-step procedure with a two-sided alternative hypothesis, should you be able to reject the hypothesis that the population mean is 20 pounds using a significance level of 0.05? Why or why not? The conf
> Data on the disk and website show reaction distances in centimeters for the dominant hand for a random sample of 40 independently chosen college students. Smaller distances indicate quicker reactions. a. Make a graph of the distribution of the sample, an
> A random sample of 25 private universities was selected. A 95% confidence interval for the mean in-state tuition costs at private universities was (22,501, 32,664). Which of the following is a correct interpretation of the confidence level? (Source: Chro
> The acceptance rate for a random sample of 15 medical schools in the United States was taken. The mean acceptance rate for this sample was 5.77 with a standard error of 0.56. Assume the distribution of acceptance rates is Normal. (Source: Accepted.com) a
> 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
> 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
> Lenses used in eyeglasses, whether converging or diverging, are always designed such that the middle of the lens curves away from the eye. Why?
> 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
