According to your study unit, what's the payoff that keeps volunteers using their own time to their communities?
a. volunteers often get free lunches, tickets to events, or special t-shirts. b. people realize how well off they are compared to the people they . c. it's so rewarding, people feel emotionally high and fulfilled when they're done.
d. it's a wonderful place to meet people and network for business.

Lab reagent, hypothesis test.a reference solution used as a lab reagent is purported to have a concentration of 5 mg/dl. six samples are taken from this solution and the following concentrations are recorded: (5.32, 4.88, 5.10, 4.73, 5.15, 4.75) mg/dl.these six measurements are assumed to be an srs of all possible measurements from solution.they are also assumed to have a standard deviation of 0.2, a normal distributin, and a mean concentration equal to the true concentration of the solution.carry out a significance test to determine whether these six measurements provide reliable evidence that the true concentration of the solution is actually not 5 mg/dl.