Why is t-test used in research?
Essentially, a t-test allows us to compare the average values of the two data sets and determine if they came from the same population. Statisticians must additionally use tests other than the t-test to examine more variables and tests with larger sample sizes. For a large sample size, statisticians use a z-test.
What type of variable is a percentage?
Nominal variables are often summarized as proportions or percentages.
What is p-value in Z-test?
The uncorrected p-value associated with a 95 percent confidence level is 0.05. If your z-score is between -1.96 and +1.96, your uncorrected p-value will be larger than 0.05, and you cannot reject your null hypothesis because the pattern exhibited could very likely be the result of random spatial processes.
What to consider when choosing a statistical test?
You also want to consider the nature of your dependent variable, namely whether it is an interval variable, ordinal or categorical variable, and whether it is normally distributed (see What is the difference between categorical, ordinal and interval variables? for more information on this).
When to use independent samples in statistical analysis?
An independent samples t-test is used when you want to compare the means of a normally distributed interval dependent variable for two independent groups. For example, using the hsb2 data file, say we wish to test whether the mean for write is the same for males and females. t-test groups = female (0 1) /variables = write.
When to attribute success to intervention or posttest?
When you see a large enough difference between the pretest and posttest, you are tempted to attribute it to the intervention and claim success of the experiment. However, the half-a-dozen single-group threats challenge this interpretation. Read up on single-group Threats on WWW. Good luck.
How to perform a statistical analysis using SPSS?
Statistical analyses using SPSS This page shows how to perform a number of statistical tests using SPSS. Each section gives a brief description of the aim of the statistical test, when it is used, an example showing the SPSS commands and SPSS (often abbreviated) output with a brief interpretation of the output.