Subject #15: 7.5 hours Subject #27: 6 hours Subject #48: 7 hours Subject #80: 6.5 hours Subject #91: 7.5 hours Subject #82: 8 hours Subject #23: 5.5 hours Select the two TRUE statements. a.) Mary would use the sample standard 0 deviation to calculate a t-statistic. b.) The value for the degrees of freedom O for Mary's sample population is six. c.) The t-distribution that Mary uses has 0 skinnier tails than a standard distribution. d.) The t-distribution that Mary use 0 taller than a standard distribution