Missing data

Question 1

What are the types of missing data?

Answer 1

1) Structurally Missing
2) Missing Completely At Random (MCAR)
3) Missing At Random (MAR)
4) Missing Not At Random (MNAR)

Question 2

what is structurally missing data?

Answer 2

a) missing because it is supposed to be; redirected based on previous answers

Question 3

what is missing completely at random data?

Answer 3

a) if missing value is completely unrelated to any other variables in data
b) Missingness is independent of the values of any variables in the dataset.
c) unlikely to occur in practice
d) may be caused by loss of data

Question 4

what is missing at random data?

Answer 4

a) missing data is unrelated to other values of that variable
b) Missingness is dependent on values of another one or more variables in the dataset, but not the values that are missing.
c) Missing and observed data may come from different distributions.

Question 5

what is missing not at random data?

Answer 5

a) the missing data for a given variable is related to the other values of that variable.
b) Missingness may also be dependent on values of another one or more variables in the dataset.
c) Often a consideration for longitudinal studies
d) Also known as informative dropout.

Question 6

How might you visualise missing data?

Answer 6

a) shadow matrix
b) scatterplot
c) density plot