12. What is the value of the appropriate statistic for a hypothesis test on a one-sided right-handed mean with a significance level of 5% for a sample size of 15? (The variance of the population is unknown and the population distribution is assumed to be normal) t=-1,7531 z=-1,645 t=1,7613 t=1,7531 z=1,645 t=1,3450 t=-1,7613