Although millions of elephants once roamed across Africa, by the mid-1980s elephant populations in African nations had been devastated by poaching. Elephants are important to African ecosystems. In tropical forests, elephants create clearings in the canopy that encourage new tree growth. In savannas, elephants reduce bush cover to create an environment that is favorable to browsing and grazing animals. In addition, the seeds of many plant species depend on passing through an elephant’s digestive tract before germination.
The status of the elephant now varies greatly across the continent. In some nations, strong measures have been taken to effectively protect elephant populations; for example, Kenya has destroyed over five tons of elephant ivory confiscated from poachers in an attempt to deter the growth of illegal ivory trade (Associated Press, July 20, 2011). In other nations the elephant populations remain in danger due to poaching for meat and ivory, loss of habitat,
and conflict with humans. Table 3.13 shows elephant populations for several African nations in 1979, 1989, 2007, and 2012 (ElephantDatabase.org website).
The David Sheldrick Wildlife Trust was established in 1977 to honor the memory of naturalist David Leslie William Sheldrick, who founded Warden of Tsavo East National Park in Kenya and headed the Planning Unit of the Wildlife Conservation and Management Department in that country. Management of the Sheldrick Trust would like to know what these data indicate about elephant populations in various African countries since 1979.
Managerial Report
Use methods of
- 1. The mean annual change in elephant population for each country in the 10 years from 1979 to 1989, and a discussion of which countries saw the largest changes in elephant population over this 10-year period.
- 2. The mean annual change in elephant population for each country from 1989 to 2007, and a discussion of which countries saw the largest changes in elephant population over this 18-year period.
- 3. The mean annual change in elephant population for each country from 2007 to 2012, and a discussion of which countries saw the largest changes in elephant population over this 5-year period.
- 4. A comparison of your results from parts 1, 2, and 3, and a discussion of the conclusions you can draw from this comparison.
Trending nowThis is a popular solution!
Chapter 3 Solutions
Essentials of Statistics for Business and Economics
- 3 (Sharpe-ratio) Suppose that X1, X2,..., is a lognormal geometric random walk with parameters (μ, o²). Specifically, suppose that X = Xo exp(rı + ...Tk), where Xo is a fixed constant and r1, T2, ... are IID N(μ, o²). Find the Sharpe-ratios of rk and log(Xk) — log(Xo) respectively, assuming the risk free return is 0.arrow_forwardi need help with question 2arrow_forward4 (Value-at-Risk and Expected Shortfall) Suppose X Find VaR0.02(X) and ES0.02 (X). ~ Uniform(-1, 1).arrow_forward
- 亚 ח Variables Name avgdr employ educ exerany Label AVG ALCOHOLIC DRINKS PER DAY IN PAST 30 EMPLOYMENT STATUS EDUCATION LEVEL EXERCISE IN PAST 30 DAYSarrow_forwardVariables Name wage hours IQ KWW educ exper tenure age married black south urban sibs brthord meduc feduc Label monthly earnings average weekly hours IQ score knowledge of world work score years of education years of work experience years with current employer age in years =1 if married =1 if black =1 if live in south =1 if live in SMSA number of siblings birth order mother's education father's educationarrow_forwardInformation for questions 4 • • Please Download "wages" from Canvas (the link to this dataset is right below the HWA1 questions - it is a Microsoft excel worksheet) and store it in your favorite folder. It contains 797 observations and 16 variables. The "state" variable gives the names of the states involved in this dataset. • You need to have excel on your computer to open this dataset. i. You should use File > Import > Excel Spreadsheet etc. as done in class 3 convert this file into a Stata dataset. Once you are done, write the final STATA code that makes the transformation of an excel file to a STATA file possible. ii. Write a code that will close the log file that has been open since Question 1 part ii.arrow_forward
- The mean, variance, skewness and kurtosis of a dataset are given as - Mean = 15, Variance = 20, SKewness = 1.5 and Kurtosis = 3.5 calculate the first four raw moments. (Note- Please include as much detailed solution/steps in the solution to understand, Thank you!)arrow_forwardWrite codes to perform the functions in each of these cases i. ii. Apply cd command to tell STATA the filepath associated with your "favorite folder" (use the same name for the favorite folder that we have been using in class) Apply log using command to tell stata that you are creating a log file to record the codes and the outcomes of these codes. Make sure your log file is called loghwa1_W25.smcl. Do not forget to include the replace option. iii. Get help for the "regress" command & include a screenshot of the outcome of this code iv. V. Open a stata file stored in STATA memory called pop2000.dta Continue from question iv. Save this file in your favorite folder (current working directory) using a different name & a replace optionarrow_forwardAre there any unusually high or low pH levels in this sample of wells?arrow_forward
- 0 n AM RIES s of of 10 m Frequency 40 Frequency 20 20 30 10 You make two histograms from two different data sets (see the following figures), each one containing 200 observations. Which of the histograms has a smaller spread: the first or the second? 40 30 20 10 0 20 40 60 0 20 20 40 60 60 80 80 100 80 100arrow_forwardTIP the aren't, the data are not sym 11 Suppose that the average salary at a certain company is $100,000, and the median salary is $40,000. a. What do these figures tell you about the shape of the histogram of salaries at this company? b. Which measure of center is more appro- priate here? c. Suppose that the company goes through a salary negotiation. How can people on each side use these summary statistics to their advantage? 6360 be 52 PART 1 Getting Off to a Statistically Significant Sarrow_forward12 Suppose that you know that a data set is skewed left, and you know that the two measures of center are 19 and 38. Which figure is the mean and which is the median?arrow_forward
- Linear Algebra: A Modern IntroductionAlgebraISBN:9781285463247Author:David PoolePublisher:Cengage Learning