📚 Concepts

📚 Data

• A collection of information in the form of numbers, facts, or observations. It can be:

  • Raw Data: Unprocessed data.

  • Grouped Data: Organized into intervals for ease of analysis.

📚 Frequency

• The number of times a particular value or group of values appears in a data set.

📚 Class Interval

• A group or range of values into which data is divided (e.g., 0–10, 10–20). Each has:

  • Lower Class Limit

  • Upper Class Limit

📚 Class Width

• The difference between the upper and lower boundary of a class.

• Class Width = Upper Limit − Lower Limit

📚 Midpoint (Class Mark)

• The average of the lower and upper limits of a class.

• Class Mark = (Lower Limit + Upper Limit) / 2

📚 Mean (Average)

• Represents the central value of data. In statistics, we often use the "assumed mean method" for faster calculations with grouped data.

📚 Median

• The value that lies in the middle of the data when arranged in ascending order. It divides the data into two equal parts.

📚 Mode

• The value that appears most frequently in the data. In grouped data, it’s estimated using a formula for the modal class.

📚 Cumulative Frequency

• The running total of frequencies. It helps in determining the median using the "less than" or "more than" cumulative table.

📚 Histogram & Frequency Table

• Visual representations of data using bars. Class intervals are on the x-axis, frequencies on the y-axis.

✍️ Formulas