There were two widely divergent influences on the early development of statistical methods. Statistics had a mother who was dedicated to keeping orderly records of governmental units (state and statistics come from the same Latin root, status) and a gentlemanly gambling father who relied on mathematics to increase his skill at playing the odds in games of chance. The influence of the mother on the offspring, statistics, is represented by counting, measuring, describing, tabulating, ordering. and the taking of censuses —— all of which led to modern descriptive statistics. From the influence of the father came modern inferential statistics, which is based squarely on theories of probability.
Descriptive statistics involves tabulating, depicting, and describing collections of data. These data may be quantitative, such as measures of height, intelligence, or grade level - variables that are characterized by an underlying continuum - orthe data may represent qualitative variables, such as sex, college major, or personality type. Large masses of data must generally undergo a process of summarization or reduction before they are comprehensible. Descriptive statistics is a tool for describing or summarizing or reducing to comprehensible form the properties of an otherwise unwieldy mass or data. Inferential statistics is a formalized body of methods for solvi...
Glacier National park in Montana shares boundaries with Canada, an American Indian reservation, and a national forest. Along the North Fork of the Flathead River, the park also borders about 17,000 acres of private lands that are currently used for ranching, timber, and agriculture. This land is an important part of the habitat and migratory routes for several endangered species that frequent the park. These private lands are essentially the only ones available for development in the region.
With encouragement from the park, local landowners initiated a land-use planning effort to guide the future of the North Fork. The park is a partner in an interlocal agreement that calls for resource-managing agencies to work together and with the more than 400 private owners in the area. A draft plan has been prepared, with the objective of maintaining traditional economic uses but limiting new development that would damage park resources. Voluntary action by landowners, in cooperation with the park and the county, is helping to restrict small-lot subdivisions, maintain wildlife corridors, and minimize any harmful impact on the environment.
The willingness of local landowners to participate in this protection effort may have been stimulated by concerns that Congress would impose a legislative solution.
Nevertheless, many local residents ...
If the salinity of ocean waters is analyzed, it is found to vary only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation —— conversion of liquid water to water vapor. In this manner, the salinity is increased, since the salts stay behind. If this is carried to the extreme, of course, white crystals of salt would be left behind.
The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas of high rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by evaporation, or decreased by the addition of fresh water by precipitation or runoff.
Normally, in tropical regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.
A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is...
- M: Look, I’m sorry to bother you about this, but that music’s really loud.
- W: I didn’t realize you could hear it.
What will the woman probably do?
- M: George is going to work in New York for the summer.
- W: Can he do that and go to summer school?
What does the woman imply about George?
- W: Shouldn’t someone pick up the clothes from the cleaner’s?
- M: Don’t look at me!
What does the man mean?
- W: Congratulations! I understand you got a job. When do you start work?
- M: You must be thinking of someone else. I’m still waiting to hear.
What does the man mean?
- W: Are you sure you corrected all the typing errors? You want to make a good impression.
- M: I’d better read through the paper
What is the man going to do?转自:考试网 - [Examw.Com]
- M: I think the whole class is going on the field trip next Friday.
- W: I’m not so sure. Not everyone has paid the transportation fee.
What does the woman imply?
- W: Could you bring my calculator back? I need it to do my math homework tonight.
- M: I don’t know how to put this; but, uh, I dropped it, and now the “...