Basic Statistics And Probability By Shahid Jamal Pdf 745 Exclusive May 2026

Why dispersion? Two datasets can have same mean but different spread.

Key Formulas:

Shortcut method (Assumed mean method) – extensively used in Shahid Jamal’s book.

Problem 745 Exclusive (Typical):
Calculate variance and standard deviation for: 5, 7, 9, 11, 13.
Solution: Mean = 9. Deviations: -4, -2, 0, 2, 4. Squares sum = 16+4+0+4+16=40. Variance = 40/5=8. SD = √8 = 2.828. Why dispersion

| Pros | Cons | | :--- | :--- | | Exam-Oriented: Does not waste time on complex derivations; focuses strictly on what is asked in exams. | Not for Academics: If you are looking for deep theoretical knowledge (B.Sc. or M.Sc. level), this is not the right book. It is strictly for aptitude. | | Short Tricks: Includes time-saving methods (Tricks) essential for exams with tight time limits. | Error Risk: Informal PDF compilations sometimes contain minor printing errors or typos in answers, requiring cross-verification. | | Language: The language is generally simple, bridging the gap between English and Hindi medium students (often using Hinglish). | Lack of Advanced Probability: May not cover very advanced probability cases that rarely appear in exams but might be needed for higher-level tests like CAT or Banking. |

Definition: Statistics is the science of collecting, organizing, analyzing, and interpreting numerical data to make decisions.

Key Divisions:

Important Terms (Page ~745 often covers definitions):

Example Problem (Exclusive Type from Shahid Jamal):
Classify the following: Number of cars in a parking lot (discrete), weight of a newborn (continuous), color of eyes (qualitative).

| Measure | Formula (Raw Data) | Best Used For | |---------|--------------------|----------------| | Mean (x̄) | Σx / n | Symmetric data, no outliers | | Median | Middle value | Skewed data | | Mode | Most frequent | Categorical data | Shortcut method (Assumed mean method) – extensively used

Weighted Mean: x̄_w = Σ(wx) / Σw

Exclusive Problem (745 Style):
The mean of 20 numbers is 15. If each number is multiplied by 3 and then 4 is added, find the new mean.

Solution: New mean = 3×15 + 4 = 49.

Shahid Jamal is widely respected in the competitive exam circuit for his ability to simplify complex mathematical concepts.