.True or false - for the dataset:13, 13, 15, 15, 16, 16, 16, 17, 18, 22

a)The maximum value of the dataset above is 22.If the analyst makes one mistake and record it as 2.2, then the mistake will change the mean and the median of the dataset. Show calculations.

b)If the variance of a dataset is zero, then all observations must also be zero.

c)The standard deviation of dataset cannot be negative.

d)The variance of a dataset is always positive.