[ML] AIOps Log Rate Analysis: improve explanation of log rate spike/d…

…ip (#186342)

## Summary

Related issue: #182714

This PR adds a `Log rate change` column to Log rate analysis results
table.

The log rate change is calculated by getting the number of buckets for
baseline/deviation using the timerange and interval and then comparing
the average rates per bucket for baseline vs deviation.

<img width="1466" alt="image"
src="https://github.com/elastic/kibana/assets/6446462/9b2f1b80-d1d5-407e-908c-f611e54be4f3">

<img width="1471" alt="image"
src="https://github.com/elastic/kibana/assets/6446462/56cb2c35-3758-4b24-9f50-2f99242af1b3">



### Checklist

Delete any items that are not applicable to this PR.

- [ ] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [ ]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [ ] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed
- [ ] Any UI touched in this PR is usable by keyboard only (learn more
about [keyboard accessibility](https://webaim.org/techniques/keyboard/))
- [ ] Any UI touched in this PR does not create any new axe failures
(run axe in browser:
[FF](https://addons.mozilla.org/en-US/firefox/addon/axe-devtools/),
[Chrome](https://chrome.google.com/webstore/detail/axe-web-accessibility-tes/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US))
- [ ] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [ ] This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))
- [ ] This was checked for [cross-browser
compatibility](https://www.elastic.co/support/matrix#matrix_browsers)

---------

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/aiops/public/components/log_rate_analysis/log_rate_analysis_results.tsx

@@ -186,7 +186,11 @@ export const LogRateAnalysisResults: FC<LogRateAnalysisResultsProps> = ({
   );
   const [shouldStart, setShouldStart] = useState(false);
   const [toggleIdSelected, setToggleIdSelected] = useState(resultsGroupedOffId);
-  const [skippedColumns, setSkippedColumns] = useState<ColumnNames[]>(['p-value']);
+  const [skippedColumns, setSkippedColumns] = useState<ColumnNames[]>([
+    'p-value',
+    'Baseline rate',
+    'Deviation rate',
+  ]);
 
   const onGroupResultsToggle = (optionId: string) => {
     setToggleIdSelected(optionId);

x-pack/plugins/aiops/public/components/log_rate_analysis_results_table/get_baseline_and_deviation_rates.ts

@@ -0,0 +1,97 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { i18n } from '@kbn/i18n';
+import { LOG_RATE_ANALYSIS_TYPE } from '@kbn/aiops-log-rate-analysis';
+
+export function getLogRateChange(
+  analysisType: typeof LOG_RATE_ANALYSIS_TYPE[keyof typeof LOG_RATE_ANALYSIS_TYPE],
+  baselineBucketRate: number,
+  deviationBucketRate: number
+) {
+  let message;
+  let factor;
+
+  if (analysisType === LOG_RATE_ANALYSIS_TYPE.SPIKE) {
+    if (baselineBucketRate > 0) {
+      factor = Math.round(((deviationBucketRate / baselineBucketRate) * 100) / 100);
+      message = i18n.translate(
+        'xpack.aiops.logRateAnalysis.resultsTableGroups.logRateFactorIncreaseLabel',
+        {
+          defaultMessage: '{factor}x higher',
+          values: {
+            factor,
+          },
+        }
+      );
+    } else {
+      message = i18n.translate(
+        'xpack.aiops.logRateAnalysis.resultsTableGroups.logRateDocIncreaseLabel',
+        {
+          defaultMessage:
+            '{deviationBucketRate} {deviationBucketRate, plural, one {doc} other {docs}} rate up from 0 in baseline',
+          values: { deviationBucketRate },
+        }
+      );
+    }
+  } else {
+    if (deviationBucketRate > 0) {
+      // For dip, "doc count" refers to the amount of documents in the baseline time range so we use baselineBucketRate
+      factor = Math.round(((baselineBucketRate / deviationBucketRate) * 100) / 100);
+      message = i18n.translate(
+        'xpack.aiops.logRateAnalysis.resultsTableGroups.logRateFactorDecreaseLabel',
+        {
+          defaultMessage: '{factor}x lower',
+          values: {
+            factor,
+          },
+        }
+      );
+    } else {
+      message = i18n.translate(
+        'xpack.aiops.logRateAnalysis.resultsTableGroups.logRateDocDecreaseLabel',
+        {
+          defaultMessage: 'docs rate down to 0 from {baselineBucketRate} in baseline',
+          values: { baselineBucketRate },
+        }
+      );
+    }
+  }
+
+  return { message, factor };
+}
+
+export function getBaselineAndDeviationRates(
+  analysisType: typeof LOG_RATE_ANALYSIS_TYPE[keyof typeof LOG_RATE_ANALYSIS_TYPE],
+  baselineBuckets: number,
+  deviationBuckets: number,
+  docCount: number | undefined,
+  bgCount: number | undefined
+) {
+  let baselineBucketRate;
+  let deviationBucketRate;
+  if (analysisType === LOG_RATE_ANALYSIS_TYPE.SPIKE) {
+    if (bgCount !== undefined) {
+      baselineBucketRate = Math.round(bgCount / baselineBuckets);
+    }
+
+    if (docCount !== undefined) {
+      deviationBucketRate = Math.round(docCount / deviationBuckets);
+    }
+  } else {
+    // For dip, the "doc count" refers to the amount of documents in the baseline time range so we set baselineBucketRate
+    if (docCount !== undefined) {
+      baselineBucketRate = Math.round(docCount / baselineBuckets);
+    }
+
+    if (bgCount !== undefined) {
+      deviationBucketRate = Math.round(bgCount / deviationBuckets);
+    }
+  }
+
+  return { baselineBucketRate, deviationBucketRate };
+}

x-pack/plugins/aiops/public/components/log_rate_analysis_results_table/log_rate_analysis_results_table_groups.tsx

@@ -149,6 +149,7 @@ export const LogRateAnalysisResultsGroupsTable: FC<LogRateAnalysisResultsTablePr
     {
       'data-test-subj': 'aiopsLogRateAnalysisResultsGroupsTableColumnGroup',
       field: 'group',
+      width: skippedColumns.length < 3 ? '34%' : '50%',
       name: (
         <>
           <FormattedMessage