Final answer:
To find the variance (σ²) of the number of heads when a coin is flipped 30 times, use the formula for variance: Variance (σ²) = n * p * (1 - p). Substitute the values and calculate to get the answer.
Step-by-step explanation:
To find the variance (σ²) of the number of heads when a coin is flipped 30 times, we need to use the formula for variance:
Variance (σ²) = n * p * (1 - p)
where n is the number of trials (30) and p is the probability of getting a head (0.5 for a fair coin).
Substituting the values into the formula, we get:
Variance (σ²) = 30 * 0.5 * (1 - 0.5) = 30 * 0.5 * 0.5 = 7.5
Therefore, the variance (σ²) of the number of heads when a coin is flipped 30 times is 7.5. The answer is option A.