Sign test: overview
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Sign test 


Independent variable  
2 paired groups  
Dependent variable  
One categorical of ordinal level  
Null hypothesis  
If the dependent variable is measured on a continuous scale:
 
Alternative hypothesis  
If the dependent variable is measured on a continuous scale:
 
Assumptions  
Sample of pairs is a simple random sample from the population of pairs. That is, pairs are independent of one another  
Test statistic  
$W = $ number of difference scores that is larger than 0  
Sampling distribution of $W$ if H0 were true  
The exact distribution of $W$ under the null hypothesis is the Binomial($n$, $p$) distribution, with $n =$ number of positive differences $+$ number of negative differences, and $p = 0.5$.
If $n$ is large, $W$ is approximately normally distributed under the null hypothesis, with mean $np = n \times 0.5$ and standard deviation $\sqrt{np(1p)} = \sqrt{n \times 0.5(1  0.5)}$. Hence, if $n$ is large, the standardized test statistic $$z = \frac{W  n \times 0.5}{\sqrt{n \times 0.5(1  0.5)}}$$ follows approximately a standard normal distribution if the null hypothesis were true.  
Significant?  
If $n$ is small, the table for the binomial distribution should be used: Two sided:
If $n$ is large, the table for standard normal probabilities can be used: Two sided:
 
Equivalent to  
Two sided sign test is equivalent to
 
Example context  
Do people tend to score higher on mental health after a mindfulness course?  
SPSS  
Analyze > Nonparametric Tests > Legacy Dialogs > 2 Related Samples...
 
Jamovi  
Jamovi does not have a specific option for the sign test. However, you can do the Friedman test instead. The $p$ value resulting from this Friedman test is equivalent to the two sided $p$ value that would have resulted from the sign test. Go to:
ANOVA > Repeated Measures ANOVA  Friedman
 
Practice questions  