There are many computer programs for performing statistical analysis on data. The most popular are SPSS, SAS, MiniTab and STATA
Descriptive statistics; normally the first task in analysis of data. Describing single variables involves determining distributional characteristics of the variables such as central tendency and. where possible visual techniques (box plots, stem&leaf, etc.) are used to make the central tendency and distributional characteristics clear. Summary statistics for the variables are calculated--central tendency (mean, median, mode) and distributional characteristics (frequency distributions, % in classifications, range, IQR, standard deviation etc.). This information on the variables allows one to: (1) describe the data, (2) decide if a hypothesis is testable using the data one has and (3) provides necessary information for selection of appropriate statistics to test the hypothesis.
Inferential statistics: Inferring is the process of making a guess (hopefully, educated) about a population (target) based on information collected in a sample. There are many different possible statistics that could be used such but some form of significance is commonly used.
Basic concepts:
Hypothesis, an educated guess about a possible relationship between two variables (1.Amount of food intake determines ones weight 2. Gender determines how much financial support one would recieve from friends and relatives to go to college )Typically for a computer statistical analysis of survey data one:Independent Variable, the cause, prior in time, determiner of the other variable in your hypothesis (1..food intake, 2. gender)
Dependent Variable, the determined, later in time, determined by the other variable in your hypothesis (1. weight 2. amount of financial help one recieves from relatives and friends to go to college )
Control Variable, a variable you have reason to believe is also related to your variables. You control for this variable to examine it's relationship to your other variables (1. amount of exercise, metabolic rate, height 2. age, marital status, socioeconomic status of respondant, friends and relatives)
Significance (statistical), if a distribution could have occurred by chance (randomly or accidentally) then the distribution is not significant. If a distribution is not likely to have occurred by chance it is significant. Say you are rolling dice for real bucks and your opponent gets his points every time. Such a case is not likely to have occurred by chance (that is what is ment by statistical significance), probably he/she is cheating (that is your personal significance). Typical statistical significance levels for sociology studies would be .05 or less meaning that what occurred in the table distribution, correlation, etc. could have occurred by chance in only 5 out of 100 replications of your study-there is a likely relationship between the variables. One is variable is a "likely a cause" of the other variable. Always "likely" since statistics are proabilities and there are other possiblities such as that someother variable caused both of the variables you are examining.
Representativeness and bias, the sample should be created so as to represent the population (target) as closely as possible. The best mathmatical way to ensure this is by collecting a randon sample (this is a very precise technique of Equal Probality of SelectionMethod in which each member of the target has the same likelyhood of selection)
Sample Size, in general the bigger the better.
Error Margin, the range withen which the best statistical guess occurs. Examples include:
Guessing peoples weight at the fair withen 3 lbs (this error margin actually is a range of 5 lbs as seen below where my weight is 165)
163 164 165 166 167
Predicting election results (for example saying Grey Davis was predicted to obtain 60 to 68% of the vote for Governor.Confidence Level, a measure of strength of your conviction that the real occurence will occur withen your error margin. Generally this is 95% level of confidence, stated as "We are 95% confident that the election results will be between 60 and 68% [error margin] for Grey Davis for Governor"

Inferential statistics techniques are designed to specify estimates and confidence in estimates, of a population based on data collected from a sample. Estimates of the distribution of all possible samples, the sampling distribution, are made from the one samples variability, sample A, B, or C in graphic above. One can then estimate the likelihood of finding a difference equal to or greater then that found in the sample data. For example a survey might collect a random sample of 100 surveys from a University containing 5000 students. The central tendency, mean, median or mode, is used to estimate the central tendency of the population of 5000.
Table conventions: Creating and Reading a Table(interpreting the distributions in a table)
