1. What is Cumulative Frequency?

Cumulative frequency is the running total of frequencies in a frequency distribution. It shows the number of observations that lie above (or below) a particular value in a data set.

2. How to Calculate Cumulative Frequency

The formula for cumulative frequency is:

Where:

• \( CF_i \) — Cumulative frequency at the ith observation
• \( f_j \) — Frequency of the jth observation

Steps:

1. List all values and their frequencies
2. Start with the first frequency as the first cumulative frequency
3. Add each subsequent frequency to the previous cumulative frequency

3. Importance of Cumulative Frequency

Details: Cumulative frequency helps in analyzing the distribution of data, constructing ogives (cumulative frequency graphs), and finding medians, quartiles, and percentiles.

4. Using the Calculator

Tips: Enter frequencies separated by commas (e.g., "5,12,8,3"). The calculator will compute and display the cumulative frequencies in a table.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between frequency and cumulative frequency?
A: Frequency counts how often each value occurs, while cumulative frequency is the running total of frequencies.

Q2: Can I use this for grouped data?
A: Yes, you can enter the frequencies for each group or class interval.

Q3: How is cumulative frequency used in statistics?
A: It's used to determine percentiles, quartiles, and to create cumulative distribution functions.

Q4: What is a cumulative frequency graph called?
A: It's called an ogive (pronounced "oh-jive").

Q5: Can cumulative frequency decrease?
A: No, cumulative frequency is always non-decreasing as you move through the data set.