Question

A large number of disease-free individuals were enrolled in a study beginning January 1, 1970, and were followed for 30 years to assess the age at which they developed breast cancer. Individuals had clinical exams every 3 years after enrollment. For four selected individuals described below, discuss in detail, the types of censoring and truncation that are represented.

(a) A healthy individual, enrolled in the study at age 30, never developed breast cancer during the study.

(b) A healthy individual, enrolled in the study at age 40, was diagnosed with breast cancer at the fifth exam after enrollment (i.e., the disease started sometime between 12 and 15 years after enrollment).

(c) A healthy individual, enrolled in the study at age 50, died from a cause unrelated to the disease (i.e., not diagnosed with breast cancer at any time during the study) at age 61.

(d) An individual, enrolled in the study at age 42, moved away from the community at age 55 and was never diagnosed with breast cancer during the period of observation.

(e) Confining your attention to the four individuals described above, write down the likelihood for this portion of the study.

Answer 1

A) Here the have a look at at age = 30

We are identified the Type 1 censoring,

Therefore, censoring time = 60

for the reason that checkup will keep until it reaches the age 60

b)Here the study at age = 40

We are diagnosed the Interval censoring

Therefore , censoring time= [52 ,55}

as the exam will preserve until the 12 years to 15 years after it reaches the age 40.

C)Here the look at at age = 50

We are recognized the Random censoring

Therefore, censoring time=61 as the patient dies abruptly

d)Here the observe at age = 42.

We are recognized the Random censoring

Therefore, censoring time = 55

as the man or woman moves faraway from at 55..So he does not within the procedure.

e)These observations are left on the age 30,forty,50 and 42

These are the attentions of likelihood for this part of the above look at.