Day 6: CFA Level I Quant Study Plan: Descriptive Statistics - CFA Level 1 90 Days

 Day 6 - Level 1 CFA in 90 Days

Day 6 begins a new Quantitative Methods block. After several days of time value of money, today shifts into descriptive statistics: how data is summarized, interpreted, and compared. The Quant questions cover mean, weighted mean, geometric mean, variance, standard deviation, coefficient of variation, skewness, and kurtosis.

This is a study-plan blog post, not official CFA curriculum material. Use it to structure your preparation, then rely on your CFA materials, notes, or question bank for the actual readings and practice problems.

Checklist

Spend 10-15 minutes preparing your study setup.

Materials: Keep your formula sheet, calculator, question bank, and notebook ready.
Calculator check: Confirm how to enter a small data set and calculate mean and standard deviation.
Formula focus: Mark formulas for mean, weighted mean, geometric mean, variance, standard deviation, coefficient of variation, and range.
Flash cards: Keep your flash cards handy or ready to be prepared
Question bank filter: Select Quant questions tagged statistics, descriptive statistics, measures of central tendency, and dispersion.
Time block: Plan for study, review and questions, 2-3 hours 

Today’s goal is to understand what each statistic tells you, not just how to calculate it.

Daily Ethics reading and prep

Spend 10-15  minutes on Ethics before the Quant block.

Today’s Ethics focus: misrepresentation and data presentation.

Read one short scenario where an analyst presents performance results, charts, or statistics to a client. Ask yourself:

• Is the analyst showing the full picture?
• Are any numbers being cherry-picked?
• Are assumptions clearly explained?
• Could the presentation mislead the client?
• What disclosure would make the communication fairer?

Then complete 5 quick Ethics questions or flashcards. If you miss one, classify it mainly as a Concept gap or Reading error.

Main study block

Today’s Quantitative Methods focus is descriptive statistics.

Subtopics to study

• Arithmetic mean: The simple average of a data set.
• Weighted mean: An average where some observations carry more importance.
• Geometric mean: Useful for compound growth rates over multiple periods.
• Median and mode: Measures of central tendency that help describe the middle or most common value.
• Range: The difference between the highest and lowest values.
• Variance and standard deviation: Measures of dispersion around the mean.
• Coefficient of variation: A way to compare risk per unit of return.
• Skewness: Whether data has a longer tail on one side.
• Kurtosis: Whether data has heavier or lighter tails compared with a normal distribution.

Do not memorize statistics as isolated formulas. For each one, write one sentence explaining what it tells you.

25-question practice target

Complete 25 questions today.

Use this breakdown:

4 questions: Arithmetic mean, median, and mode
4 questions: Weighted mean
3 questions: Geometric mean and compound return interpretation
4 questions: Range, variance, and standard deviation
3 questions: Coefficient of variation
2 questions: Skewness and kurtosis interpretation
5 questions: Ethics warm-up on misrepresentation, fair presentation, and disclosure

For each Quant question, write whether it is asking for calculation or interpretation. Many statistics mistakes happen because the formula is right, but the meaning is misunderstood.

Mistake-log

After practice, log every missed or guessed question using these four labels

This log book is very important and handy to go back to difficult concepts.

• Concept gap: I did not understand what the statistic meant.
• Formula gap: I understood the idea but forgot the formula or used the wrong one.
• Calculator error: I entered data incorrectly, used the wrong calculator function, or made an arithmetic mistake.
• Reading error: I misunderstood what the question asked or confused sample/population wording.

For Ethics mistakes, use mainly Concept gap or Reading error.

Five-question review checkpoint

End the session by answering these five questions:

1. Can I explain the difference between arithmetic mean and geometric mean?
2. When would a weighted mean be more useful than a simple average?
3. What does standard deviation tell me in plain language?
4. What was my accuracy on the 20 Quant questions and 5 Ethics questions?
5. Which topic needs review tomorrow: geometric mean, standard deviation, skewness, or Ethics?