Probability • Topic 2 of 3

Experimental (Empirical

What is Experimental Probability?

Experimental probability (also called empirical probability) is the probability determined by actually performing an experiment and recording the results. It is based on observed data, not theoretical calculations.

Theoretical vs. Experimental Probability:

AspectTheoretical ProbabilityExperimental Probability
**Calculation**Favorable outcomes / Total possible outcomesObserved frequency / Total trials
**Accuracy**Exact, fixed valueApproximate, changes with trials
**Example**P(heads) = 1/2After 100 flips, 48 heads → 0.48

Formula for Experimental Probability:

\[

P(\text{Event}) = \frac{\text{Number of times event occurred}}{\text{Total number of trials}}

\]

Law of Large Numbers:

As the number of trials increases, the experimental probability gets closer to the theoretical probability.

Why Use Experimental Probability?

  • When theoretical probability is unknown or difficult to calculate
  • To test if a game or process is fair
  • In real-world situations where outcomes are not equally likely

Steps to Find Experimental Probability:

  1. Perform the experiment many times (trials)
  2. Count how many times the event occurs
  3. Divide the count by the total number of trials
Probability of Simple EventsP(Event) = Number of favourable outcomes Total number of outcomesRange: 0 ≤ P(E) ≤ 1P = 0: Impossible event P = 1: Certain eventExperiment: Toss a fair coin twiceS = {HH, HT, TH, TT} → n(S) = 4Exactly 2 heads: {HH}P = 1/4At least 1 tail: {HT,TH,TT}P = 3/4No heads: {TT}P = 1/4Complementary events: P(E) + P(not E) = 1If P(E) = 3/5, then P(E') = 1 - 3/5 = 2/5
1
Worked Example

Solve a standard problem on Experimental (Empirical.

Solution

Apply the formula/method shown in the concept section above.

Key Points

  • Understand the definition and properties of Experimental (Empirical.
  • Study the worked examples and practice similar problems.
  • Always verify your answer using the original conditions.
Tap an option to check your answer0 / 4
Q1.Empirical probability $=$
Explanation: Favourable over total trials.
Q2.A coin is tossed $100$ times and shows heads $60$ times. The empirical probability of heads is:
Explanation: $60/100=0.6$.
Q3.Empirical probability is based on:
Explanation: Observed data.
Q4.As the number of trials increases, empirical probability tends to the ___ probability.
Explanation: Approaches theoretical.