A careful shopkeeper takes delivery of a batch of 20 packets of cheese. Every morning at...

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A careful shopkeeper takes delivery of a batch of 20 packets of cheese. Every morning at 8 a.m. precisely she checks to see if any of the cheese has gone mouldy and throws away any mouldy packets. As she runs a high quality establishment, she has lots of customers and some of the cheese is sold. After ten days she decides the cheese will be too old to sell and throws out the remaining packets. A curious customer observes that the shopkeeper has created an observational plan for calculating the hazard of cheese going mouldy. (i) (ii) State, with reasons, THREE types of censoring present in this situation. [3] Assess, for EACH type of censoring listed in your answer to part (i), whether a change to the observational plan could be made which would remove that type of censoring. [3] The shopkeeper made notes at 8 a.m. each day as follows: Day Shopkeeper's notes 1 Sold three packets already -23456789: 10 (iii) Sold one more packet One went mouldy Two more mouldy ones, I hope my fridge is cold enough Seems OK, nothing to report Sold four more all to one customer! Nothing to report Another two mouldy ones this morning Sold two more Three more mouldy ones - I'll throw the rest out Calculate the Kaplan-Meier estimate of the survival function for cheese staying free from mould. [6] A careful shopkeeper takes delivery of a batch of 20 packets of cheese. Every morning at 8 a.m. precisely she checks to see if any of the cheese has gone mouldy and throws away any mouldy packets. As she runs a high quality establishment, she has lots of customers and some of the cheese is sold. After ten days she decides the cheese will be too old to sell and throws out the remaining packets. A curious customer observes that the shopkeeper has created an observational plan for calculating the hazard of cheese going mouldy. (i) (ii) State, with reasons, THREE types of censoring present in this situation. [3] Assess, for EACH type of censoring listed in your answer to part (i), whether a change to the observational plan could be made which would remove that type of censoring. [3] The shopkeeper made notes at 8 a.m. each day as follows: Day Shopkeeper's notes 1 Sold three packets already -23456789: 10 (iii) Sold one more packet One went mouldy Two more mouldy ones, I hope my fridge is cold enough Seems OK, nothing to report Sold four more all to one customer! Nothing to report Another two mouldy ones this morning Sold two more Three more mouldy ones - I'll throw the rest out Calculate the Kaplan-Meier estimate of the survival function for cheese staying free from mould. [6]

Answer rating: 100% (QA)

i The three types of censoring present in this situation are 1 Right censoring This occurs when the observation period ends before an event of interest in this case cheese going mouldy occurs In this ... View the full answer