This graph shows the likelihood of clicking after 1, 2, 3, 4, ... 14 days for this rented referral. This is statistical model built based on the referral clicking behavior, this model is also known in Mathematics as probability mass function.

- Mean: this is the average value which gives indication after how many days this referral is likely to click
- STD: this is the randomness factor which gives indication if this referral is nearly following the Mean or not. The lower this factor becomes means the referral is following, the higher this factor becomes means the referral is not following
- The Purple vertical dashed line represents the Mean value
- The Cyan highlighted area represents the range of how many days to click after for this referral
- The Green vertical dashed line represents the last click date (in days)

For the above graph as an example, we can read it as follows:

- This referral nearly clicking after 2.1 (2) days most of the time
- Around 50% of the clicks were after 1 day
- Around 22% of the clicks were after 2 days
- Around 16% of the clicks were after 3 days
- This referral never clicked after 4 days
- Most of the clicks are likely to be after between 1 and 5 days
- The current last click date is 2 days which is still inside the the Cyan highlighted area, so, this referral is still have good chance to click

In the following two examples, we will illustrate how the Activity Histogram is built compared to the Clicks Graph.

### Example # A

In this example, the referral have made 4 clicking occurrences as follows:

- First clicking occurrence after 6 days
- Second clicking occurrence after 7 days
- Third clicking occurrence after 1 day
- Fourth clicking occurrence after 3 days

Notice the Activity Histogram is showing 4 bars on 1, 3, 6, and 7, each bar is having same height (0.25 = 1 ÷ 4). Also, for the Mean = ((1 × 1) + (1 × 3) + (1 × 6) + (1 × 7)) ÷ 4 = 4.25 ≅ 4.3

### Example # B

In this example, the referral have made 7 clicking occurrences as follows:

- First clicking occurrence after 1 day
- Second clicking occurrence after 5 days
- Third clicking occurrence after 3 days
- Fourth clicking occurrence after 4 days
- Fifth clicking occurrence after 1 day
- Sixth clicking occurrence after 5 days
- Seventh clicking occurrence after 1 day

Notice the Activity Histogram is showing 4 bars on 1, 3, 4, and 5, and the bars' heights are (3 ÷ 7 ≅ 0.43), (1 ÷ 7 ≅ 0.14), (1 ÷ 7 ≅ 0.14), and (2 ÷ 7 ≅ 0.29) respectively. Also, for the Mean = ((3 × 1) + (1 × 3) + (1 × 4) + (2 × 5)) ÷ 7 = 2.857 ≅ 2.9