Question

In: Statistics and Probability

You have a dentist appointment for teeth filling. During your visit your regular doctor is not...

You have a dentist appointment for teeth filling. During your visit your regular doctor is not available but instead you are greeted by Dr. Sweeney Todd. Dr. Todd performs a tooth surgery on you but his skills in identifying which region to fill are not very accurate. He decides that he will fill the top right molar (TR) with probability 0.5, Top left molar with probability (TL) 0.6, and bottom left molar with probability (BL) 0.1. In addition, to the lack of certainty Dr. Todd takes 3 tries to fill the region identified earlier. Suppose that the event corresponding to successful surgery for a given region on a single trial, is denoted by S and if the surgery is unsuccessful, the event is denoted by N for a single region.

(a) What is P(NNS)? (That is, it is not successful for the first 2 tries and is successful for the last try)

(b) Assuming that the three trials, in order, are NNS, what is the probability that the tooth region Dr. Todd picked for filling was the top right molar (TR)?

Solutions

Expert Solution

E_1 be the event Dr. Todd performs a tooth surgery on top right molar (TR)

P[ Dr. Todd performs a tooth surgery on top right molar (TR) ] = P[ E_1 ] = 0.5

E_2 be the event Dr. Todd performs a tooth surgery on Top left molar (TL)

P[ Dr. Todd performs a tooth surgery on Top left molar (TL) ] = P[ E_2 ] = 0.6

E_3 be the event Dr. Todd performs a tooth surgery on bottom left molar (BL)

P[ Dr. Todd performs a tooth surgery on bottom left molar (BL) ] = P[ E_3 ] = 0.1

a) NNS be the event it is not successful for the first 2 tries and is successful for the last try

P[ NNS | E_1 ] = 0.5*0.5*0.5 = 0.125 ( two failures and last one success, assuming equal probability of success and failure )

P[ NNS | E_2 ] = 0.5*0.5*0.5 = 0.125 ( two failures and last one success, assuming equal probability of success and failure )

P[ NNS | E_3 ] = 0.5*0.5*0.5 = 0.125 ( two failures and last one success, assuming equal probability of success and failure  )

P[ NNS ] = P[ NNS | E_1 ]*P[ E_1 ] +  P[ NNS | E_2 ]*P[ E_2 ] +  P[ NNS | E_3 ]*P[ E_3 ]

P[ NNS ] = 0.5*0.125 + 0.6*0.125 + 0.1*0.125 = 0.15

P[ NNS ] = 0.15

b) Probability that the tooth region Dr. Todd picked for filling was the top right molar (TR) = P[ E_1 | NNS ]

P[ E_1 | A ] = P[ NNS | E_1 ]*P[ E_1 ] / P[ NNS ] = 0.5*0.125 / 0.15 = 0.4167

P[ E_1 | A ] = 0.4167


Related Solutions

During your visit to the doctor you learn that your child has a rare disorder. The...
During your visit to the doctor you learn that your child has a rare disorder. The prognosis is not good. But there are two possibilities for treatment: 1) cloning your child which will give a 100% new start or 2) starting your child on an experimental drug that has significant side effects and has not shown much efficacy for recovery. Do the research on a rare disorder in children with either of the two possible treatment and cite the source
The dentist asks you to make provisional crown for teeth #8 and #9. Your choice of...
The dentist asks you to make provisional crown for teeth #8 and #9. Your choice of coverage the polycarbonate crown. Because the teeth involved are the maxillary centrals, what are your concerns regarding these provisional crowns?
You have the following appointment slots booked during the day: 8am - 10am, 11am - 12pm,...
You have the following appointment slots booked during the day: 8am - 10am, 11am - 12pm, 1:30pm - 3pm, 2pm - 5pm. Write a program that takes as input a list of booked appointment slots, and returns slots when you are free. You solution should be generalized to work with any valid input. Assumptions: Your day starts at 8am and ends at 6pm. You can have overlapping booked appointments. Hints/suggestions: Use military time so 1:30pm is represented as 1330, for...
On a trip home during the summer break, you pay your Uncle Davea visit at...
On a trip home during the summer break, you pay your Uncle Dave a visit at his record store. When you walk in, you notice there is not one single customer. “I have run this store since the 1980s,” Uncle Dave says with a sigh. “We were the first store in this whole town to sell compact discs! But now, it feels like we’re at least a decade or two behind the times. No one buys records anymore—or even CDs!...
philosophy Scenario 1) You are a doctor. Your friend, Oscar, is also a doctor. You and...
philosophy Scenario 1) You are a doctor. Your friend, Oscar, is also a doctor. You and Oscar have a long history together. You tell each other everything. You try to work the same shifts. You exercise together. Oscar was an important part of your wedding. Oscar’s kids and yours are also best friends. Oscar even supported you when you were falsely accused of negligence, thus saving your job, your future, your kids’ future, and your very sense of well-being. Unfortunately,...
You have commenced planning the audit of FC, as part of your preliminary planning you visit...
You have commenced planning the audit of FC, as part of your preliminary planning you visit the factory. While there you notice there are large quantities of high value raw materials, genuine silks and other similar high value items stored in an unlocked store room at one end of the building. Workers would walk in select bolts of material and take them back to the cutting tables. On enquiry you are told that each night the storeman notes down the...
You are getting your wisdom teeth removed and are a participant in a clinicaltrial for three...
You are getting your wisdom teeth removed and are a participant in a clinicaltrial for three different procedures, one of which is randomly assigned to you. Of those whoundergo the first procedure, 8% get an infection; of those who undergo the second procedure,4% get an infection; of those who undergo the third procedure, 9% get an infection. (a) What is the probability that you will not get an infection. b) Unfortunately, you got an infection after removing your wisdom teeth!...
Restaurant Selector IN JAVA You have a group of friends coming to visit for your high...
Restaurant Selector IN JAVA You have a group of friends coming to visit for your high school reunion, and you want to take them out to eat at a local restaurant. You aren’t sure if any of them have dietary restrictions, but your restaurant choices are as follows: Joe’s Gourmet Burgers – Vegetarian: No, Vegan: No, Gluten-Free: No Main Street Pizza Company – Vegetarian: Yes, Vegan: No, Gluten-Free: Yes Corner Café – Vegetarian: Yes, Vegan: Yes, Gluten-Free: Yes Mama’s Fine...
If you were an investor, what are your expected impacts of the announcement (the appointment of...
If you were an investor, what are your expected impacts of the announcement (the appointment of new CFO) on the share price (up or down, good news-bad news) and justify your arguments.
You have a bacterial infection for which your doctor prescribes you a ten-day treatment of antibiotics....
You have a bacterial infection for which your doctor prescribes you a ten-day treatment of antibiotics. You take the antibiotic for three days and stop because you feel better. Briefly describe what you have inadvertently done to the bacterial population within your body.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT