Questions and Answers of The Analysis Of Biological Data

Assume that a null hypothesis for a statistical test is true. Say whether each of the following statements is true or false:a. If you reject this H0 with a test, you will be making a Type II
Do people have powers of extrasensory perception (ESP)? Some people claim to have such abilities or to know someone who has them. Some people claim that individuals who consistently get the wrong
Identify whether each of the following statements is more appropriate as the null hypothesis or as the alternative hypothesis in a test:a. Hypothesis: The number of hours preschool children spend
What effect does reducing the value of the significance level from 0.05 to 0.01 have on:a. The probability of committing a Type I error?b. The probability of committing a Type II error?c. The
Assume a random sample. What effect does increasing the sample size have ona. The probability of committing a Type I error?b. The probability of committing a Type II error?c. The power of a
Tikal National Park in Guatemala is heavily visited by tourists. Does the disturbance affect animal densities? To investigate, Hidinger (1996) compared the densities of various bird and mammal
In the toad experiment (Example 6.2), what would the P-value have been ifa. 15 toads were right-handed and the rest were left-handed?b. 13 toads were right-handed and the rest were
The following table gives either the power or the probability of a Type II error for a number of studies. Fill in the missing information. Study a.a. b.b. C.C. d.d. Power 0.750.75 0.310.31 Type II
A scientist tests the null hypothesis that the mean height of plants in their population is 0.75 meters, as it is in a nearby population observed with a complete census of all plants. Assume that
For the following alternative hypotheses, give the appropriate null hypothesis.a. Pygmy mammoths and continental mammoths differ in their mean femur lengths.b. Patients who take phentermine and
Identify whether each of the following statements is more appropriate as a null hypothesis or an alternative hypothesis.a. Hypothesis: The number of hours that grade-school children spend doing
State the most appropriate null and alternative hypotheses for each of the following experiments or observational studies:a. A test of whether cigarette smoking causes lung cancerb. An experiment
Imagine that two researchers independently carry out clinical trials to test the same null hypothesis, that COX-2 selective inhibitors (which are used to treat arthritis) have no effect on the risk
Refer to Problem 28. The researchers also found that 11 of 12 participants showed improved accuracy in the exposed nostril after 21 days.a. Carry out the four steps of hypothesis testing, to test
A group of researchers tested whether snakes tend to choose a warm resting site when both a warm site and a cool site are presented to them. Their hypotheses were H0 Snakes do not prefer the warmer
Can parents distinguish their own children by smell alone? To investigate, Porter and Moore (1981) gave new T-shirts to children of nine mothers.Each child wore his or her shirt to bed for three
A study showed that the sex ratio of children born to families in a native community of Ontario deviated significantly from the continental average ratio. A newspaper report about this study claimed
Does being told how a suspenseful story will end ruin the experience for the reader? Movie and book critics are careful to avoid giving too much away in their reviews. But the impact of such
In many animal species, individuals communicate using ultraviolet (UV) signals, such as bright patches of skin or feathers, that are visible to one another but invisible to humans. Secondi et al.
Dondorp et al. (2010) carried out a large clinical trial that compared effectiveness of two drugs, artesunate and quinine, for treatment of African children having severe malaria. They used the
A team of researchers conducted 100 independent hypothesis tests using a significance level of a. If all 100 null hypotheses were true, what is the probability that the researchers would reject none
Calculation practice: Binomial probabilities. Enterococcus bacteria are part of the normal intestinal flora of humans, but some strains can cause disease. In U.S. hospitals, 30% of pathogenic
Calculation practice: Binomial test. Do people typically use a particular ear preferentially when listening to strangers? Marzoli and Tomassi (2009) had a researcher approach and speak to strangers
In 1955, John Wayne played Genghis Khan in a movie called The Conqueror. It was not an artistic success. More unfortunately, the movie was filmed downwind of the site of 11 previous aboveground
In the United States, paper currency often comes into contact with cocaine either directly, during drug deals or usage, or in counting machines where it wears off from one bill to another. A forensic
The mite Demodex folliculorum lives in the hair follicles of humans, including the follicles of the eyelashes. (The bluish creatures in the photo on the first page of this chapter are these mites.
For the following scenarios, state whether the binomial distribution would describe the probability distribution of possible outcomes. If not, explain why not.a. The number of red cards out of the
In the garden spider Araneus diadematus, the female often attempts to eat the male before or after mating, making sex a daunting prospect for the males. (This seemingly bizarre behavior, called
As our planet warms, as it has done for the last century or so, the change in temperature will have major effects on life. There are basically three possibilities for what might happen to a species:
Imaine that there were two studies of the prevalence of melanism (solid black coat color) in leopards. One estimated that the proportion of black leopards in this population was 52%, with a 95%
Mice have litters of several pups at once. The pups are arranged in a line within the mother’s uterus, so many fetuses lie between two of their siblings. It has been shown that female fetuses
A giant vat contains large numbers of two types of bacteria, called strain A and strain B. Assume that 30% of the bacteria in the vat are strain A, and the other 70% are strain B. The vat is well
Twelve six-sided dice are rolled. Assume all of the dice are fair.a. How many threes do you expect, on average, out of these 12 rolls?b. What is the probability of rolling no threes out of the 12
A common perception is that people suffering from chronic illness may be able to delay their deaths until after a special upcoming event, like Christmas. Out of 12,028 deaths from cancer in either
In 1964, Ehrlich and Raven proposed that plant chemical defenses against attack by herbivores would spur plant diversification. In a test of this idea (Farrell et al. 1991), the number of species in
The Global Amphibian Assessment in 2005 declared that 1856 out of 5743 of the known species of amphibians worldwide are at risk of extinction.(Approximately 122 species have gone extinct already
A survey in the U.K. interviewed shoppers encountered in grocery stores about whether they had ever received injuries as a result of food or drink packaging, such as cuts sustained while cleaning up
A Royal Society for the Prevention of Cruelty to Animals (RSPCA) survey of 200 randomly chosen Australian pet owners found that 10 said that they had met their partner through owning the pet (RSPCA
One classical experiment on ESP (extrasensory perception) tests for the ability of an individual to show telepathy—to read the mind of another individual. This test uses five cards with different
In a test of Murphy’s law, pieces of toast were buttered on one side and then dropped. Murphy’s law predicts that they will land butter-side down.Out of 9821 slices of toast dropped, 6101 landed
Out of 67,410 surgeries tracked in a study in the U.K., 2832 were followed by surgical site infections (Coello et al. 2005).a. What is a 95% confidence interval for the proportion of surgeries
Each member of a large genetics class grows 12 pea plants from an independent pea family. Each family is expected to have 3/43/4 plants with smooth peas and 1/41/4 plants with wrinkled peas. a. On
Juvenile long-tailed tits (Aegithalos caudatus), a European relative of the chickadee, “help” adult birds raise offspring, such as by feeding their nestlings. What is the evolutionary advantage
In a blind taste test, do people prefer pâté or dog food? To investigate, Bohannon et al. (2010) presented 18 college-educated adults with unlabeled samples of dog food (Newman’s Own Organics
Mood variation is related to photoperiod in some people, and the likelihood of depression increases in the winter months. As a result, people often assume that suicide rates increase in winter. A
Biff and Dilara were having an argument over what fraction of people would likely go out of their way to drive over a live organism if it were standing innocently by the side of the road. Dilara,
Biff and Dilara were arguing over a news feed about a population of catfish (Silurus glanis) in France that had figured out how to hunt feral pigeons. A submerged catfish lying in wait would rush
The Cook pine tree is native to New Caledonia but has been planted as an ornamental in many countries. The trees tend to lean to one side as they grow. Johns et al. (2017) measured the tilt in 256
Refer to Practice Problem 16.a. Plot the null probability distribution for this case.b. What is the meaning of this distribution?Data from problem 16In 1964, Ehrlich and Raven proposed that plant
Bombardier beetles Pheropsophus jessoensis eject a hot chemical spray from the tip of their abdomens when attacked. Does this sometimes improve their survival? As part of a study to test this
You are working in a lab and need to have five clean Petri plates for your experiment tomorrow. You have eight plates prepared, but previous experience tells you that 10% of them will, on average, be
The parasitic nematode Camallanus oxycephalus infects many freshwater fish, including shad. The following table gives the number of nematodes per fish (Shaw et al. 1998):a. Produce a graph of the
Soccer reaches its apex every four years at the World Cup, attracting worldwide attention and fanatic devotion. The World Cup is widely thought to be the event that decides the best soccer team in
Some people have suggested that Alzheimer disease may be at least partially caused by a contagious agent. If this were true, one might expect that people who come into contact with brain tissue may
Each of the following examples could be addressed with a goodness-of-fit test. From the information given, how many categories and how many degrees of freedom would each test have? Explain your
Practice Problem 5 from Chapter 7 gave data about the death rates of people working on the movie The Conqueror. Test whether the cancer rates in this group were different from the expected rate of
The following list gives the number of degrees of freedom and the test statistic for several goodness-of-fit tests. Find the P-value for each test as specifically as possible from Statistical Table
Imagine that a small hospital’s emergency room has an average of 20 admissions per Saturday night. If you were a doctor working overtime on such a Saturday night, you might want to know the
In North America, between 100 million and 1 billion birds die each year by crashing into windows on buildings, more than any other human-related cause. This figure represents up to 5% of all birds in
Practice Problem 15 from Chapter 7 gave data about death rates from cancer before and after Christmas. Use these data to test whether the holiday affects death rates. Data from problem 15A common
In the 19th century, cavalries were still an important part of the European military complex. While horses have many wonderful qualities, they can be dangerous beasts, especially if poorly treated.
If each “success” happens independently of all other successes and with the same probability, what probability distribution is expected for each of the following?a. Number of flowers in
Cummings et al. (2003) estimate that the relative risk of death in a vehicle crash for occupants 16 to 34 years old who were wearing a seatbelt was 0.36 compared to those not wearing a seatbelt.
Truffles are a great delicacy, sending thousands of mushroom hunters into the forest each fall to find them. A set of plots of equal size in an oldgrowth forest in Northern California was surveyed to
Are the outcomes of hospital care different on weekends than weekdays?In a random sample of 500 patients who experienced severe medical complications after admission to acute care wards in three U.S.
A more recent study of Feline High-Rise Syndrome (FHRS) (see Chapter 1, Example 1.2) included data on the month in which each of 119 cats fell (Vnuk et al. 2004). The data are in the accompanying
Hurricanes hit the United States often and hard, causing some loss of life and enormous economic costs. They are ranked in severity by the Saffir–Simpson scale, which ranges from Category 1 to
Refer to Assignment Problem 22. The researchers used gas chromatographic analysis to extract and identify eight major volatile chemicals present in the host plants (tomato). They tested each of these
In snapdragons, variation in flower color is determined by a single gene (Hartl and Jones 2005). RR individuals are red, Rr (heterozygous) individuals are pink, and rr individuals are white. In a
Spot the flaw. Tabershaw and Lamm (1977) compared the observed and expected numbers of different leukemia types in a study group of workers who had been exposed to benzene during their employment.
Seedlings of the parasitic plant Cuscuta pentagona (dodder) hunt by directing growth preferentially toward nearby host plants. Lacking eyes, or even a nervous system, how do they detect their
Consider an isolated population of humans in which some individuals are infected with a specific parasite species (e.g., malaria or a filarial worm). Think of two biological hypotheses for why the
The National Electronic Injury Surveillance System (Consumer Product Safety Commission 2018) recorded the number of injuries associated with computers and video games. A sample of these injuries (all
The National Electronic Injury Surveillance System tracks injuries reported from hospital admissions across the United States (Consumer Product Safety Commission 2018). For the data in 2017, we
African swine fever virus is a disease of wild boars that is spread in part by contact between living pigs and the carcasses of dead pigs. As part of an investigation into the patterns of contact
Calculation practice: Odds ratio. Use the data from Problem 1 on coffee drinking and prostate cancer.a. What are the odds of advanced prostate cancer for high-coffee consumers?b. What are the odds
Calculation practice: relative risk. Wilson et al. (2011) followed a set of male health professionals for 20 years. Of all the men in the study, 7890 drank no coffee and 2492 drank on average more
The common pigeon found in most American cities is derived from a domesticated European species released in North America. As a result, the pigeons in North America have variations in coloration
Female Australian redback spiders, Latrodectus hasselti, are about 50 times larger than males and often eat the males during mating. This might sound like a horrible accident, but males could gain
Malaria, which kills more than a million people each year worldwide, is caused by a Plasmodium that spreads between hosts by infected mosquitoes. The more people bitten by each infected mosquito, the
Fires are a common and important part of many ecosystems. Many species have evolved mechanisms for dealing with fire. Reed frogs, a species living in West Africa, have been observed hopping away from
Some fish are famously able to develop into either sex, depending on social circumstances. One study of a coral reef fish, the goby Gobiodon erythrospilus, placed juvenile fish with either an adult
Between 20 and 25 violent acts are portrayed per hour in children’s television programming. A study (Johnson et al. 2002) of the possible link between TV viewing and aggression followed the
A study by Doll et al. (1994) examined the relationship between moderate intake of alcohol and the risk of heart disease. In all, 410 men (209 “abstainers” and 201 “moderate drinkers”) were
Postnatal depression affects approximately 8–15% of new mothers. One theory about the onset of postnatal depression predicts that it may result from the stress of a complicated delivery. If so,
Migraine with aura is a potentially debilitating condition, yet little is known about its causes. A case-control study compared 93 people who suffer from chronic migraine with aura (cases) to a
The hypothetical plots below show the relative frequencies of subjects assigned to two experimental groups (treatment and control). The frequency of negative outcomes (red) and positive outcomes
In animals without paternal care, the number of offspring sired by a male increases as the number of females he mates with increases. This fact has driven the evolution of multiple matings in the
New technical advances in diagnosis and screening are often expensive, and so their benefits must be evaluated. A study of a new screening procedure for heart disease, computerized tomographic
Treatment of patients whose injury might cause massive blood loss has involved giving them plasma transfusions after they had been admitted to the emergency room.Sperry et al. (2018) investigated
Some people feel that they have good intuition about when others are lying, while others do not feel they have this ability. Are the more “intuitive” people better able to detect lies? Each of
Spot the flaw. Scottish researchers compared rates of depression between 94 undergraduates who regularly kept diaries and 41 students who did not. They found that people who kept diaries were more
It is well known, and scientifically documented, that yawning is contagious. When we see someone else yawn, or even think about someone yawning, we are very likely to yawn ourselves. (In fact, we
Aging workers of the Neotropical termite, Neocapritermes taracua, develop blue crystal-containing glands (“backpacks”) on their backs. When they fight intruding termites and are hampered, these
Day care centers expose children to a wider variety of germs than the children would be exposed to if they stayed at home more often. This has the obvious downside of more frequent colds and other
Keenan et al. (2001) used anesthesia to investigate which brain hemisphere is involved in self-recognition. Ten subjects were randomly assigned to two groups. The left hemisphere was anesthetized in
Eggebeen et al. (2010) found that men who at some point in their lives are fathers are more likely to have altruistic social relationships and be involved in community service organizations. This
Male Drosophila become sterile when exposed to moderately high temperatures, because sperm are damaged by heat at much lower temperatures than other cells.Rohmer et al. (2004) asked whether flies
Spot the flaw. After golden monkeys fight with each other, opponents seem to reconcile. Ren et al. (1991) tested whether the behavior of golden monkeys after spontaneous conflicts differed from
Vampire bats, as their name implies, feed almost exclusively on blood. A bat must feed every day or it will starve to death, but bats are not always successful at finding a blood meal. Perhaps for

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