统计学文字题

简答题

1、Why do we take use of the sample survey instead of the census? Can you list some examples? Answer：Economic

Finite or a very large population

Time-consuming of the population survey

The possible destructive nature of the survey process

The sample results reliable

2、sample methods

Simple random sampling ----simple

Stratified sampling ----we can acquire the information about the relationships among strata. Systematic random sampling

Cluster sampling ---there are similarities among cluster members . increase sampling error.

3、Index number: An index number measures how much a variable changes over time.(we calculate an index number by finding the ratio of the current value to a based value)

4、kinds of index: Qualitative index quantitative index 或者compositive and individual index或者price index 和volume index

5、Quantitative indicator (Aggregate or Absolute indicator) It reflects the size or level of the objective things (Total instance, total out put value, population)

Qualitative indicator :It is the ratio of two quantitative indicators. It reflects the relationships, ratio, developing speed and inner structure of the objective things. (Labor productive, per capita national income)

6、Quantitative index: quantitative indicator of current period/ quantitative indicator of base period

Qualitative index: qualitative indicator of current period/qualitative indicator of base period 7、Index system: Index system is built up on the basis of the indicator system.

The indicator system is composed by a series of interrelated, interactive indicators. (There are two kinds of relationship among the indicators: functional relationship and complementary relationship.)

8、time series: An variable that is measured over time in sequential order is called a time series or dynamic series.

9、Four components of a time series ：Long-term trend

Cyclical variation

Seasonal effect

Random or Irregular variation

10、What is relative/absolute analysis ：P96公式

11、four levels of data and their characteristic:

Nominal level data :Data that is classified into categories and cannot be arranged(排列) in any particular order. Nominal data are numbers that merely indicate name or label differences in kind. Such as gender, eye color and religious application .

Ordinal level data : involves data arranged in some order/ rank, but the differences between data values cannot be determined(确定) or are meaningless. Such as job class, product quality ratings and degrees of agreement .

Interval level : Similar to the ordinal level, with the additional property(性质) that meaningful amounts of differences between data values can be determined. There is no natural zero point. It permits addition and subtraction(增加和减少)