Interpreting SPSS Output
Output Consists of two sections:
- The first box tells how many records contain valid data for what was entered. In the Valid row, the number tells how many records contain complete data. The missing category tells how many records have missing or invalid data. If there is a number greater than zero in the missing section, the missing data should be located and entered into the data set.
- The second box of data indicates the frequency distributions of the data. There are five columns:
- First column indicates the values of the variables in a sorted order. There is one row for each value and two additional rows for Total and Missing data at the bottom of the output.
- The second column gives the frequency of each value.
- The third column indicates the percentage of records that hold that value.
- The fourth column gives the percentage of valid data with that value (excludes missing data fields)
- The fifth column gives a cumulative percentage, which includes scores that are equal to, or smaller than the current value.
Central Tendency for Frequency Table:
- To get this data you must specify it by 1) selecting "analyze" 2) selecting "frequencies" 3) selecting "statistics" and choosing the ones you want. In the output the left-hand column will name the measures of central tendency that were included in the analysis. Each column after that will contain the information from each variable that was chosen to get measures of central tendency. Variable labels will be indicated at the top of each column.
Output for ONLY Mean, Median, Mode and Standard Deviation:
- Variables are presented in the left-hand column and each variable is given a row. Each type of output (Mean, median, etc.) is given a column that is presented after the variable column. The output for each value should be read across the rows according to the type of output presented in each column.
- The results of the analysis are presented in the form of a correlation matrix. Each variable entered is given a row and a column. So, if two variables are chosen, there will be a 2X2 matrix. Each cell contains three rows (the correlation, the significance level and N, or subject number). To compare two variables, find one variable in the left-hand column and the second variable in the top row. Follow each variable across the column, or down the row. The cell in which the two meet is the cell where the data for that relationship is given. The top row in each cell indicates the correlation coefficient. To see whether the correlation is significant, the second row indicates the significance level. If the value is less than .05, then the correlation is significant and there is a relationship. Be sure to indicate the direction of the relationship when reporting results.
Independent Samples T-test:
- The first section will be labeled "Group Statistics" and will give the descriptive statistics for the dependent variable(s) for each value of the independent variable.
- The second section gives the results of the t-test. The columns labeled t, df, and Sig(2-tailed) are the important columns to pay attention to. They will give you the "answer" to the t-test and provide information about the value of t, the degrees of freedom, and the significance level (p value), respectively. If the value of p is less than .05, then the test is significant and the means are not equal. In this way, it can be concluded that the "treatment" had an effect and you should indicate which mean is higher when reporting results.