Moving to another question will save this response. Question 10 Question 10 of 20 5 points Save Answer It is thought that teenagers sleep more than adults on average. A study is done to verify this. A sample of 16 teenagers has a mean of 89 hours of sleep and a standard deviation of 1.2. A sample of 12 adults has a mean of 6.9 hours of sleep and a standard deviation of 0.6. Indicate if the hypothesis test is for O a. two proportions Ob. Independent group means, population standard deviations and/or variances unknown Oc independent group means, population standard deviations, and/or variances known O d. single mean