0
votes

I did a change on my webpage on a given date. Now a want to measure if there is a significant impact on the usage due to the change. How can I do a sampled t-test in Application Insights? Splitting the time series data on a given date than comparing the two sets?

1

1 Answers

2
votes

In the KQL there is a built-in function for calculating Welch's t-test: welch_test().

Given a table T with a metric m and a change date d, you can calculate the test by aggregating the metric before and after the change:

T
| summarize m1 = avgif(m, Timestamp < d), 
    v1 = varianceif(m, Timestamp < d), 
    c1 = countif(Timestamp < d), 
    m2 = avgif(m, Timestamp > d), 
    v2 = varianceif(m, Timestamp > d), 
    c2 = countif(Timestamp > d)
| extend pValue=welch_test(m1,v1,c1,m2,v2,c2)