A safety specialist was concerned about cars' speeds on a certain busy stretch of road. They randomly selected 21 cars and measured their speeds at the same point on the road. Each car was from a different time period and day, so the specialist is willing to consider the sample as representative. The speeds in the sample were strongly skewed to the left with a sample mean of x = 96.5 km/hr. There were also a few outliers.

The specialist is considering using their data to make a confidence interval for the mean speed. a Which conditions for constructing a t interval have been met?
a. The data is a random sample from the population of interest.
b. The sampling distribution of x is approximately normal.
c. Individual observations can be considered independent.