Hi @Vijay Kumar.K
Thanks for posting the question on the AppDynamics Community.
Refer to Specify Percentiles to Collect for information on calculating the 98th percentile value. The doc states as follows:
By default, app agents capture the 95th percentile. You can indicate 5 whole numbers between 1 and 99 as Percentiles to Collect on the Configuration > Slow Transaction Thresholds window. You can apply the configuration changes to all existing business transactions or only to new transactions discovered after the configuration change.
Hope it helps. Let us know if you have further queries.
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