B$4.[$Total $20$ marks$]$

a$)$ Given the following medical data records, fill in the two missing values $($cf$.$ the empty boxes$)$ using attribute mean$/$mode for the same class defined by the "Fever" and "Disease" attributes.

Table II Medical Data Records with Missing Values

$(4$ marks$)$

b$)$ Given the following medical data records with a noisy "Age" value$=105($highlighted$),$ smooth the "Age" values by using bin means. Show the steps and list ALL smoothed "Age" values for equi$-$depth partitioning with $4$ bins.

Table III Medical Data Records with Noisy Value

$(4$ marks$)$

c$)$ With respect to a selected medical application context, give an example of a $3$D data cube modelled for a data warehouse. Describe the $3$ dimension tables and the fact table involved for your selected context.

$(8$ marks$)$

d$)$ Based on your answer in part $($c$),$ describe how OLAP operations "Roll Up$"$ and "Drill Down" work to answer a possible query arising from a medical application context.

$(4$ marks$)$