In order to view analysis of contact's activities, navigate to Contacts. Then select the contact that interests you, click on more, and select activity chart.
The activity chart will provide you with data on the number of specific activities performed by or in relation to a contact within a selected period of time:
Additionally the chart also presents information on the average number of performed activities.
The chart looks different for each contact, because it is based only on the activities pertaining to a particular contact.