A random sample of 18 purchases showed the amounts in the table (in $) The mean is $47.81 and the standard deviation is $20.39 a) How many degrees of freedom does the t-statistic have? b) How many degrees of freedom would the t-statistic have if the sample size had been 2? 40 36 80 89 62 08 42210 42.24 24 92 25.16 82.62 25.65 47.75 30.03 70.37 52.17 72.79 14.45 34 19 55 83 56.83 a) The t-statistic has degrees of freedom (Simplify your answer.) b) If the sample size had been 2. the t-statistic would have degrees of freedom (Simplify your answer.)