1. What is the First Quartile (Q1)?

Definition: The first quartile (Q1) is the value below which 25% of the data falls when arranged in ascending order.

Purpose: Q1 is a measure of central tendency that helps understand data distribution and identify outliers.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q1 \) — First quartile value (same units as data)
• \( n \) — Number of data points (dimensionless)
• Value — Data value at calculated position (same units as data)

Explanation: The data is first sorted, then the position of Q1 is calculated. If the position isn't an integer, linear interpolation is used between adjacent values.

3. Importance of Quartile Calculation

Details: Quartiles help analyze data spread, identify skewness, and build box plots for visual data representation.

4. Using the Calculator

Tips: Enter comma-separated numerical values (e.g., 5, 8, 12, 3, 9). The calculator will sort the data and compute Q1.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between Q1 and median?
A: The median is Q2 (50th percentile), while Q1 is the 25th percentile.

Q2: How is Q1 calculated for even/odd datasets?
A: The formula accounts for all cases using interpolation when needed.

Q3: What if my data has non-numeric values?
A: The calculator automatically filters out non-numeric entries.

Q4: Can I use different delimiters?
A: Currently only commas are supported. Remove any other delimiters first.

Q5: How precise is the calculation?
A: Results are shown with 4 decimal places for precision.