Question

If an unauthorized person accesses a computer account with the correct username and password, can this intrusion be detected? The time between keystrokes, the time a key is depressed, the frequency of various keywords are measured and compared with those of the account owner. The following times between keystrokes were recorded when a user typed the username and password 0.24, 0.22 0.26, 0.34, 0.35, 0.32 seconds.

(a) Determine the five point summary

Answer 1

The five-point summary of the times between keystrokes is minimum 0.22 seconds, first quartile 0.25 seconds, median 0.29 seconds, third quartile 0.345 seconds, and maximum 0.35 seconds. This summary helps identify the distribution of the data and can be used to detect anomalies in typing patterns that might indicate unauthorized access.

Step-by-step explanation:

To determine the five-point summary of the times between keystrokes, we must first order the data from lowest to highest: 0.22, 0.24, 0.26, 0.32, 0.34, 0.35 seconds. The five-point summary consists of the following:

• Minimum: The smallest data point, which is 0.22 seconds.
• First Quartile (Q1): The median of the lower half of the data. For our dataset, Q1 is the average of the 2nd and 3rd values, which is (0.24 + 0.26) / 2 = 0.25 seconds.
• Median: The middle value when the data is ordered. Since we have an even number of observations, the median is the average of the 3rd and 4th values, which is (0.26 + 0.32) / 2 = 0.29 seconds.
• Third Quartile (Q3): The median of the upper half of the data. For our dataset, Q3 is the average of the 5th and 6th values, which is (0.34 + 0.35) / 2 = 0.345 seconds.
• Maximum: The largest data point, which is 0.35 seconds.

The five-point summary is useful in describing the distribution of data and for detecting outliers. Intrusions using the correct username and password might be detected if the intruder's typing pattern significantly deviates from this five-point summary, especially when compared to the authentic user's historical pattern.