"Conservationists have despaired over destruction of tropical rain forest by logging, clearing, and burning." These words begin a report on a statistical study of the effects of logging in Borneo. Here are data on the number of tree species in 12 unlogged forest plots and 9 similar plots logged 8 years earlier: Unlogged Logged 22 18 22 20 15 21 13 13 19 13 19 15 17 4 18 14 18 15 15 10 12 Does logging significantly reduce the mean number of species in a plot? Assume equal population variances and use a = 0.05. Use the difference: logged - unlogged

"Conservationists have despaired over destruction of tropical rain forest by logging, clearing, and burning." These words begin a report on a statistical study of the effects of logging in Borneo. Here are data on the number of tree species in 12 unlogged forest plots and 9 similar plots logged 8 years earlier: Unlogged Logged 22 18 22 20 15 21 13 13 19 13 19 15 17 4 18 14 18 15 15 10 12 Does logging significantly reduce the mean number of species in a plot? Assume equal population variances and use a = 0.05. Use the difference: logged - unlogged

Big Ideas Math A Bridge To Success Algebra 1: Student Edition 2015

1st Edition

ISBN:9781680331141

Author:HOUGHTON MIFFLIN HARCOURT

Publisher:HOUGHTON MIFFLIN HARCOURT

Chapter11: Data Analysis And Displays

Section11.4: Two-ways Tables

Problem 12E

See similar textbooks

Similar questions

Engineers are interested in comparing the mean hydrogen production rates per day for three different heliostat sizes. From the past week’s records, the engineers obtained the amount of hydrogen produced per day for each of the three heliostat sizes. That they computed and compared the sample means, which showed that the mean production rate per day increased with heliostat sizes. a. Identify the type of study described here. b. Discuss the types of interference that can and cannot be drawn from this study.
Accounting Today identified the top accounting firms in 10 geographic regions across the United States. All 10 regions reported growth in 2014. The Southeast and Gulf Coast regions reported growth of 12.36% and 5.8%, respectively. A characteristic description of the accounting firms in the Southeast and Gulf Coast regions included the number of partners in the firm. The file AccountingPartners3 contains the number of partners. (Data extracted from bit.ly/1BoMzsv) Assuming that the population variances from both offices are equal, at the 0.10 level of significance, is there evidence of a difference between Southeast region accounting firms and Gulf Coast accounting firms with respect to the mean number of partners? Referring to Table 10-1, which of the following is an appropriate null hypothesis? Question 2 options: 1) H0 : μI - μII > 0 2) H0 : μI - μII < 0 3) H0 : μI - μII = 0…
Accounting Today identified the top accounting firms in 10 geographic regions across the United States. All 10 regions reported growth in 2014. The Southeast and Gulf Coast regions reported growth of 12.36% and 5.8%, respectively. A characteristic description of the accounting firms in the Southeast and Gulf Coast regions included the number of partners in the firm. The file AccountingPartners3 contains the number of partners. (Data extracted from bit.ly/1BoMzsv) Assuming that the population variances from both offices are equal, at the 0.10 level of significance, is there evidence of a difference between Southeast region accounting firms and Gulf Coast accounting firms with respect to the mean number of partners? Referring to Table 10-1, at the α = 0.10 level, the correct critical value(s) is (are) Question 3 options: 1) 1.6860, -1.6860. 2) 1.3042. 3) 2.0244, -2.0244. 4)…
Accounting Today identified the top accounting firms in 10 geographic regions across the United States. All 10 regions reported growth in 2014. The Southeast and Gulf Coast regions reported growth of 12.36% and 5.8%, respectively. A characteristic description of the accounting firms in the Southeast and Gulf Coast regions included the number of partners in the firm. The file AccountingPartners3 contains the number of partners. (Data extracted from bit.ly/1BoMzsv) Assuming that the population variances from both offices are equal, at the 0.10 level of significance, is there evidence of a difference between Southeast region accounting firms and Gulf Coast accounting firms with respect to the mean number of partners? Referring to Table 10-1, judging from the way the data were collected, which test would likely be most appropriate to employ? Question 1 options: 1) F test for the ratio of two variances 2) Separate-variance t test for…
4: The average depth of the Hudson Bay is 305 feet. Climatologists were interested in seeing if theeffects of warming and ice melt were affecting the water level. Fifty-five measurements over a periodof weeks yielded a sample mean of 306.2 feet. The population variance is known to be 3.57. Can it beconcluded at the 0.05 level of significance that the average depth has increased?
8- Conduct residual analysis for the best fitted model. Comment on the normality assumption and constant error variances . Comment on this 4 graph on the the normality assumption and constant error variances
14. In a study examining the effect of alcohol on reaction time, Liguori and Robinson (2001) found that even moderate alcohol consumption significantly slowed response time to an emergency situation in a driving simulation. In a similar study, researchers measured reaction time 30 minutes after participants consumed one 6-ounce glass of wine. Again, they used a standardized driving simulation task for which the regular population averages μ = 400 msec. The distribution of reaction times is approximately normal with σ = 40. Assume that the researcher obtained a sample mean of M = 422 for the n = 25 participants in the study. a. Are the data sufficient to conclude that the alcohol has a significant effect on reaction time? Use a two-tailed test with α = .05. b. Compute Cohen’s d to estimate the size of the effect. c. Finally, based on your conclusion (i.e., reject or retain the null hypothesis) state what kind of error (type 1 or 2) you might be making.
4.Table 5.13 (page 237 in the textbook) shows the observed pollution indexes of air samples in two areas of a city. Using a Statistical software, test the hypothesis that the mean pollution indexes are the same for the two areas using? = 0.05. Check the normality of data sets using a graphical method (hint: side-by-side boxplot). Be sure to include the edited computer output and to interpret the results. Area A 2.92 1.88 5.35 3.87 4.69 2.86 5.81 3.55 Area B 1.84 1.95 4.26 3.18 3.44 3.69 4.95 4.47
Pulmonary DiseaseTwenty-two young asthmatic volunteers were studied toassess the short-term effects of sulfur dioxide (SO2) exposure under various conditions [12]. The baseline data inTable 12.30 were presented regarding bronchial reactivity to SO2 stratified by lung function (as defined by forcedexpiratory volume / forced vital capacity [FEV1/FVC]) atscreening.*12.6 Test the hypothesis that there is an overall mean difference in bronchial reactivity among the three lung-functiongroups.
A biologist is interested in compare the mean growth of 4 species of a shrub in the Upper Michigan climates. She selects a random sample of 40 seeds from each of the 4 species and grow them under similar conditions to reduce confounding. After three months she measures the growth and conducts an Analysis of Variance (ANOVA) test to compare the mean growth. Suppose she set up the null hypotheses as H0:μ1=μ2=μ3=μ4 and her computed FF-test statistic is F=3.24 What are the two degrees of freedom of the ANOVA?df1= df2= Use FF-distribution to find the pp-value of the given test-statistic.p= Which of the following describes how the FF-test statistic is computed? A. It is the the ratio of the variation among samples over the variation within samples.B. It is the the sum of the variation among samples and the variation within samples.
Two companies produce small motorcycles of varying quality. An important measure of quality is the top speed the motorcycle can obtain on a flat surface. Do the following data provide evidence that the average top speed of cycles from these two companies differ? Report the p-value to two decimal places. Do not assume equal variances. Top Speed in mph from Company 1 Top Speed in mph from Company 2 21.5 53.0 20.3 40.1 49.6 49.3 43.8 51.6 50.5 52.6 52.5 50.6 47.8 37.0 33.2
Pulmonary Hypertension. In the paper “Persistent Pulmonary Hypertension of the Neonate and Asymmetric Growth Restriction” (Obstetrics&Gynecology, Vol. 91, No. 3, pp. 336–341), M. Williams et al. reported on a study of characteristics of neonates. Infants treated for pulmonary hypertension, called the PH group, were compared with those not so treated, called the control group. One of the characteristics measured was head circumference. The mean head circumference of the 10 infants in the PH group was 34.2 centimeters (cm). a. Assuming that head circumferences for infants treated for pulmonary hypertension are normally distributed with standard deviation 2.1 cm, determine a 90% confidence interval for the mean head circumference of all such infants. b. Obtain the margin of error, E, for the confidence interval you found in part (a). c. Explain the meaning of E in this context in terms of the accuracy of the estimate. d. Determine the sample size required to have a margin of error of…