Descriptive statistical analysis is to the data itself, using statistical indicators to describe its characteristics of the analysis method, this description seems simple, in fact, is a lot of advanced analysis of the basic work, many advanced analysis methods for the data have certain assumptions and conditions, which can be judged by descriptive statistical analysis, we will also find , the results of many analysis methods are more or less interspersed with some descriptive analysis results.
Descriptive statistics focuses on the three main elements of data:
1. Focus on trends
2. Discrete trends
3. Distribution of data
The indicators that describe the trend of concentration are mean, majority, median, including the mean of truncation, geometric mean, harmonic mean, etc.
The indicators describing discrete trends include frequency, relative number, variance, standard deviation, standard error, total distance, four percentile spacing, four percentile, percentile, coefficient of variation, etc.
Note: The indicators for continuous and discrete variables are different.
Since many statistical analyses have a normal distribution hypothesis, we often also pay attention to the distribution characteristics of the data, common kurtosis coefficients and skewness coefficients to describe the extent of the data deviating from the normal distribution, or you can use the Bootstrap method to calculate the results compared with the results calculated by the classical statistical method, if the difference is obvious Indicates that the original data is biased or has an extremum
The process of SPSS for descriptive statistical analysis is in the analysis-descriptive Statistics menu, although these several processes use different, but basically can output the commonly used indicator result.
I. Analysis-descriptive statistics-frequency
This process can output the main indicator of the trend and discrete trend of continuous variable concentration, and can also output the histogram and kurtosis value of the judging distribution.
and skewness values, in addition, the main function of the process is the output frequency tables, the results are as follows:
Ii. analysis-Descriptive statistics-description
Looks like the process is Orthodox. Describes the statistical analysis process, in fact, the output of the process is not much, and no chart can be called, the only special is that the process can standardize the transformation of data, and save as a new variable.
Iii. analysis-descriptive statistics-exploration
Exploratory analysis is based on descriptive statistics of the original data and further describes the data, which provides more detailed results than the first two processes.
SPSS Data Analysis (4)-Descriptive statistical analysis of continuous variables