Question

which of the following is an example of probability-based inference?
a.measuring the gas mileage of a large number of cars
b.using the probability of a head to predict that 50 out of 100 coin flips will come up heads
c.computing the mean lifetime of a type of lightbulb
d.based on 20 lightbulb tests, stating that the expected lifetime of a type of bulb is 800 hours

Explanation:

Probability-based inference uses sample data to make probabilistic conclusions about a larger population. Option A is just data collection, Option B uses a known probability to predict a single trial outcome rather than inferring about a population, Option C is a descriptive statistic of a sample. Option D uses a small sample (20 lightbulbs) to infer the expected lifetime (a probabilistic claim) for the entire type of bulb, which fits probability-based inference.

Answer:

D. Based on 20 lightbulb tests, stating that the expected lifetime of a type of bulb is 800 hours