A study tests whether teenagers sleep more than adults on average. A sample of 16 teenagers has a mean of 8.9 hours slept and a standard deviation of 1.2. A sample of 12 adults has a mean of 6.9 hours slept and a standard deviation of 0.6. Indicate if the hypothesis test is for __________.

Group of answer choices

independent sample means, population standard deviations unknown

matched or paired samples

single mean

independent sample means, population standard deviations known