The R output below tells us that we need a total of 128 people (64 per group) for a specific set of study parameters: Type I error rate (alpha) = 0.05, standard deviation = 2, size of the effect to detect = 1, power = 80%. Use this output to answer the next three questions. > power.t.test(power=0.80, sd=2, delta = 1, sig.level=0.05) Two-sample t test power calculation n = 63.76576 delta = 1 sd = 2 sig.level 0.05 power = 0.8 alternative two.sided NOTE: n is number in each group Question 8 1 pts What will happen to the required sample size if we decide we want to have 90% power? Sample size needed will go up Sample size needed will go down Sample size needed will stay the same Question 9 1 pts What will happen to the required sample size if we assume the true effect (what we want to detect) is a difference of 2? Sample size needed will go up Sample size needed will go down Sample size needed will stay the same Question 10 1 pts What will happen to the required sample size if we assume the data have a standard deviation of 3? Sample size needed will go up Sample size needed will go down Sample size needed will stay the same