You create a report to show the types of devices users have been coming from over the past 30 days — whether they were on computers or mobile phones, for example. In this report, which of these is a “metric” in Google Analytics?
Explanation:
Metrics are quantitative measurements. The metric Sessions is the total number of sessions. The metric Pages/Session is the average number of pages viewed per session.
user metrics are calculated in two basic ways:
As overview totals
where the metric is displayed as a summary statistic for your entire site, such as bounce rate or total pageviews.
In association with one or more reporting dimensions
where the metric value is qualified by selected dimension(s).
Read more here: https://support.google.com/analytics/answer/1033861