Concept explainers
Delaying Adulthood. The convict surgeonfish is a common tropical reef fish that has been found to delay metamorphosis into adult by extending its larval phase. This delay often leads to enhanced survivorship in the species by increasing the chances of finding suitable habitat. In the paper “Delayed Metamorphosis of a Tropical Reef Fish (Acanthurus triostegus): A Field Experiment” (Marine Ecology Progress Series, Vol. 176, pp. 25–38), M. McCormick published data that he obtained on the larval duration, in days, of 90 convict surgeonfish. The data are given on the WeissStats site. At the 5% significance level, do the data provide sufficient evidence to conclude that the
- a. Employ the Wilcoxon signed-rank test.
- b. Employ the t-test.
- c. Compare your results from parts (a) and (b).
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Introductory Statistics (10th Edition)
- Part (b)arrow_forwardA local church is interested in determining how length of residence in the present community relates to church attendance. Using a random sample of 15 individuals, they gathered data on how many times in the previous 5 weeks each individual attended church services. The data are provided below. Length of residence in the community Less than 2 years 2-5 years More than 5 years 0 0 1 1 2 3 3 3 3 4 4 4 4 5 4 Using the 5-step model, determine whether and how church attendance is related to length of residence in the community. Use 5% and 1% levels of statistical significance. What are the assumptions for this problem?arrow_forwardChapter 5, Section 1, Exercise 019 MORE BENEFITS OF EATING ORGANICUsing specific data, we find a significant difference in the proportion of fruit flies surviving after 13 days between those eating organic potatoes and those eating conventional (not organic) potatoes. This exercise asks you to conduct a hypothesis test using additional data. In this case, we are testing H0 : po= pcHa: po > pc where po and pc represent the proportion of fruit flies alive at the end of the given time frame of those eating organic food and those eating conventional food, respectively. Use a 5% significance level.Effect of Organic Bananas After 25 DaysAfter 25 days, the proportion of fruit flies eating organic bananas still alive is 0.42, while the proportion still alive eating conventional bananas is 0.40. The standard error for the difference in proportions is 0.029.What is the value of the test statistic?Round your answer to two decimal places. z= What is the p-value?Round your answer to…arrow_forward
- Chapter 5, Section 1, Exercise 018 MORE BENEFITS OF EATING ORGANICUsing specific data, we find a significant difference in the proportion of fruit flies surviving after 13 days between those eating organic potatoes and those eating conventional (not organic) potatoes. This exercise asks you to conduct a hypothesis test using additional data. In this case, we are testing H0 : po= pcHa: po > pc where po and pc represent the proportion of fruit flies alive at the end of the given time frame of those eating organic food and those eating conventional food, respectively. Use a 5% significance level.Effect of Organic Soybeans After 5 DaysAfter 5 days, the proportion of fruit flies eating organic soybeans still alive is 0.92, while the proportion still alive eating conventional soybeans is 0.84. The standard error for the difference in proportions is 0.023.What is the value of the test statistic?Round your answer to two decimal places. z= What is the p-value?Round your answer to…arrow_forwardSection 2.2 (77) Frogs have been breeding like flies at the Enormous State University (ESU) campus! Each year, the pledge class of the Epsilon Delta fraternity is instructed to tag all the frogs residing on the ESU campus. Two years ago, they managed to tag all 50,000 of them (with little Epsilon Delta Fraternity tags). This year’s pledge class discovered that last year’s tags had all fallen off, and they wound up tagging a total of 75,000 frogs. a)Find an exponential model for the frog population. b)Assuming exponential population growth and that all this year’s tags have fallen off, how many tags should Epsilon Delta order for next year’s pledge class?arrow_forward4a,4b,4carrow_forward
- 6B A study was conducted that measured the total brain volume (TBV) (in mm3) of patients that had schizophrenia and patients that are considered normal. Table #1 contains the TBV of the normal patients and Table #2 contains the TBV of schizophrenia patients ("SOCR data Oct2009," 2013). Table #1: Total Brain Volume (in mm3) of Normal Patients 1663407 1583940 1299470 1535137 1431890 1578698 1453510 1650348 1288971 1366346 1326402 1503005 1474790 1317156 1441045 1463498 1650207 1523045 1441636 1432033 1420416 1480171 1360810 1410213 1574808 1502702 1203344 1319737 1688990 1292641 1512571 1635918 Table #2: Total Brain Volume (in mm3) of Schizophrenia Patients 1331777 1487886 1066075 1297327 1499983 1861991 1368378 1476891 1443775 1337827 1658258 1588132 1690182 1569413 1177002 1387893 1483763 1688950 1563593 1317885 1420249 1363859 1238979…arrow_forwardRamp metering is a traffic engineering idea that requires cars entering a freeway to stop for a certain period of time before joining the traffic flow. The theory is that ramp metering controls the number of cars on the freeway and the number of cars accessing the freeway, resulting in a freer flow of cars, which ultimately results in faster travel times. To test whether ramp metering is effective in reducing travel times, engineers conducted an experiment in which a section of freeway had ramp meters installed on the on-ramps. The response variable for the study was speed of the vehicles. A random sample of 15 cars on the highway for a Monday at 6 p.m. with the ramp meters on and a second random sample of 15 cars on a different Monday at 6 pm with the meters off resulted in the following speeds (in miles per hour). (a) Uraw side-by-side Doxplots of each data set Does there appear to be a merence in the speeds? Are there any outlers? Choose the correct Dox plot below. A. 0 Off 15 30 45…arrow_forwardRamp metering is a traffic engineering idea that requires cars entering a freeway to stop for a certain period of time before joining the traffic flow. The theory is that ramp metering controls the number of cars on the freeway and the number of cars OA. Yes, there appears to be a high outlier in the Meters Off data. B. Yes, there appears to be a low outlier in the Meters On data. OC. Yes, there appears to be a high outlier in the Meters On data. OD. No, there does not appear to be any outliers. (b) Are the ramp meters effective in maintaining a higher speed on the freeway? Use the a=0.05 level of significance. State the null and alternative hypotheses. Choose the correct answer below. OA. Ho Hon Hoff H₁ Hon > Hoff OC. Ho Hon Hoff H₁ Hon Hoff # Determine the P-value for this test. *** P-value= (Round to three decimal places as needed.) OB. Ho Hon = Hoff H₁ Pon > Hoff O D. Ho Hon Hoff H₁-Hon > Hoff Choose the correct conclusion. O A. Do not reject Ho. There is sufficient evidence at the…arrow_forward
- Section 4.1 Question 10arrow_forwardIn his doctoral thesis, L. A. Beckel (University of Minnesota, 1982) studied the social behavior of river otters during the mating season. An important role in the bonding process of river otters is very short periods of social grooming. After extensive observations, Dr. Beckel found that one group of river otters under study had a frequency of initiating grooming of approximately 1.7 for each 10 minutes. Suppose that you are observing river otters for 30 minutes. Let r = 0, 1, 2, ... be a random variable that represents the number of times (in a 30-minute interval) one otter initiates social grooming of another. a) Find the probabilities that in your 30 minutes of observation, one otter will initiate social grooming four times, five times, and six times. (Round your answers to four decimal places.) P(4) = P(5) = P(6) = b) Find the probability that one otter will initiate social grooming less than four times during the 30-minute observation period. (Round your answer…arrow_forwardIn his doctoral thesis, L. A. Beckel (University of Minnesota, 1982) studied the social behavior of river otters during the mating season. An important role in the bonding process of river otters is very short periods of social grooming. After extensive observations, Dr. Beckel found that one group of river otters under study had a frequency of initiating grooming of approximately 1.7 for each 10 minutes. Suppose that you are observing river otters for 30 minutes. Let r = 0, 1, 2, ... be a random variable that represents the number of times (in a 30-minute interval) one otter initiates social grooming of another. a) What is ?? b) Write out the formula for the probability distribution of the random variable r. P(r) = _________ c) Find the probability that one otter will initiate social grooming four or more times during the 30-minute observation period. (Round your answer to four decimal places.)arrow_forward
- Linear Algebra: A Modern IntroductionAlgebraISBN:9781285463247Author:David PoolePublisher:Cengage Learning