Hansen (2006) describes a study to assess the migration and survival of salmon released from fish farms located in Norway. The mingling of escaped farmed salmon with wild salmon raises several concerns. First, the assessment of the abundance of wild salmon stocks will be biased if there is a presence of large numbers of farmed salmon. Second, potential interbreeding between farmed and wild salmon may result in a reduction in the health of the wild stocks. Third, diseases present in farmed salmon may be transferred to wild salmon. Two batches of farmed salmon were tagged and released in two locations, one batch of 1,996 fish in northern Norway and a second batch of 2,499 fish in southern Norway. The researchers recorded the time and location at which the fish were captured by either commercial fisherman or anglers in fresh water. Two of the most important pieces of information to be determined by the study were the distance from the point of the fish’s release to the point of its capture and the length of time it took for the fish to be captured.
- a. Identify the population that is of interest to the researchers.
- b. Describe the sample.
- c. What characteristics of the population are of interest to the researchers?
- d. If the sample measurements are used to make inferences about the population characteristics, why is a measure of reliability of the inferences important?
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An Introduction to Statistical Methods and Data Analysis
- The St. Lucian Government is interested in predicting the number of weekly riders on the public buses using the following variables: • Price of bus trips ~er week • The population in the city • The monthly income of riders • Average rate to park your personal vehicle Number of weekly riders 192,000 Population of city 1,800,000 1,790,000 Price per week Monthly income of riders Average parking rates per month City $15 $5,800 $50 $6,200 $50 190,400 191,200 $15 $15 1,780,000 $6,400 $60 4 $25 $6,500 $60 177,600 176,800 1,778,000 1,750,000 1,740,000 5 $25 $6,550 $60 6. 178,400 $25 $6,580 $70 7 180,800 $25 1,725,000 $8,200 $75 175,200 174,400 $30 $30 1,725,000 $8,600 $8,800 8 $75 9. 1,720,000 $75 10 173,920 $30 1,705,000 $80 $9,200 $9,630 $10,570 $11,330 $11,600 S11,800 $11,830 $12,650 S13.000 1,710,000 1,700,000 11 172,800 163,200 $30 $80 12 $40 $80 13 161,600 $40 1,695,000 1,695,000 1,690,000 $85 14 161,600 160,800 $40 $100 15 $40 $105 1,630,000 1,640,000 1,635,000 16 159,200 $40 $105 17…arrow_forwardMany animals, including humans, tend to avoid direct eye contact and even patterns that look like eyes. Some insects, including moths, have evolved eye-spot patterns on their wings to help ward off predators. Scaife (1976) reports a study examining how eye-spot patterns affect the behavior of birds. In the study, the birds were tested in a box with two chambers and were free to move from one chamber to another. In one chamber, two large eye-spots were painted on one wall. The other chamber had plain walls. The researcher recorded the amount of time each bird spent in the plain chamber during a 60-minute session. Suppose the study produced a mean of M=34.5 minutes on the plain chamber with SS=210 for a sample of n=15 birds. (Note: If the eye spots have no effect, then the birds should spend an average of ?=30minutes in each chamber.) a. Is this sample sufficient to conclude that the eye-spots have a significant influence on the birds' behavior? Use a two-tailed test with ?=.05. b.…arrow_forwardMany animals, including humans, tend to avoid direct eye contact and even patterns that look like eyes. Some insects, including moths, have evolved eye-spot patterns on their wings to help ward off predators. Scaife (1976) reports a study examining how eye-spot patterns affect the behavior of birds. In the study, the birds were tested in a box with two chambers and were free to move from one chamber to another. In one chamber, two large eye-spots were painted on one wall. The other chamber had plain walls. The researcher recorded the amount of time each bird spent in the plain chamber during a 60-minute session. Suppose the study produced a mean of M = 37 minutes in the plain chamber with SS = 288 for a sample of n = 9 birds. (Note: If the eye-spots have no effect, then the birds should spend an average of μ = 30 minutes in each chamber.) Is this sample sufficient to conclude that the eyespots have a significant influence on the birds’ behavior? Use a two-tailed test with α = .05.…arrow_forward
- Many animals, including humans, tend to avoid direct eye contact and even patterns that look like eyes. Some insects, including moths, have evolved eye-spot patterns on their wings to help ward off predators. Scaife (1976) reports a study examining how eye-spot patterns affect the behavior of birds. In the study, the birds were tested in a box with two chambers and were free to move from one chamber to another. In one chamber, two large eye-spots were painted on one wall. The other chamber had plain walls. The researcher recorded the amount of time each bird spent in the plain chamber during a 60-minute session. Suppose the study produced a mean of M=37minutes in the plain chamber with SS=288 for a sample of n=9 birds. (Note: If the eye-spots have no effect, then the birds should spend an average of μ=30 minutes in each chamber.) Is this sample sufficient to conclude that the eye-spots have a significant influence on the birds’ behavior? Use a two-tailed test with a= .05. Compute the…arrow_forwardMany animals, including humans, tend to avoid direct eye contact and even patterns that look like eyes. Some insects, including moths, have evolved eye-spot patterns on their wings to help ward off predators. Scaife (1976) reports a study examining how eye-spot patterns affect the behavior of birds. In the study, the birds were tested in a box with two chambers and were free to move from one chamber to another. In one chamber, two large eye-spots were painted on one wall. The other chamber had plain walls. The researcher recorded the amount of time each bird spent in the plain chamber during a 60-minute session. Suppose the study produced a mean of M = 34.5 minutes on the plain chamber with SS = 210 for a sample of n = 15 birds. (Note: If the eye spots have no effect, then the birds should spend an average of μ = 30 minutes in each chamber.) a. Is this sample sufficient to conclude that the eyespots have a significant influence on the birds’ behavior? Use a two-tailed test with α =…arrow_forwardDr. Guidry conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in Nashville, Tennessee (the state capital), located in the southern United States. Dr. Guidry submits her study for publication in a scientific journal. If one of the peer reviewers is concerned about the external validity of her study, which of the following is the most important aspect of Dr. Guidry's study to consider? the number of significant findings the random sampling technique used to recruit the participants the number of people in the sample the use of three measured variablesarrow_forward
- Does the example represent an observational study or an experiment? Car accident data is obtained from the Ohio database. It is found that more accidents happened at night.arrow_forwardEconomists, Angrist and Lavy (1999) exploited an 800 year-old rule regarding classroom size to estimate the causal effect of smaller classes on student achievement. The rule, made famous by 12th century scholar Maimonides, states that one teacher is sufficient to manage a class with up to 40 students. Classes with more than 40 students will require 2 teachers. Angrist and Lavy noticed that strict application of this rule in certain areas meant that if 80 students were enrolled in a school, then the school would divide them up into two groups of 40 students per teacher. If 81 students were enrolled, however, they would be placed in three classes of 27 students each. The rule thus generated sharp discontinuities in class sizes within schools, which, the authors argue, allow them to provide causal evidence of a boost in fifth grade math and reading scores as a result of smaller class size. a. What research design is implied by the authors’ use of Maimonides’ rule to estimate the causal…arrow_forwardA social media app is conducting a study on the amount of time users spend on the app. They collect the following variables. 1. Age Years: How old they are in years? 2. Income: Monthly Income 3. Location: What country do they live in? 4. Device: Do they use an iPhone, Samsung, other? 5. Service: Who provides their mobile phone service? For example: T-Mobile, At&t, Verizon, ect 6. Hours: How many hours do they spend on the app per week. Which variable could the research construct a one proportion z-interval for? And Why would you choose that variable?arrow_forward
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