Question

A. The following probability table contains a list of events that two companies stated as reasons for eliminating jobs in the United States.    

	Automation	Outsourcing	Offshoring	Total
Company A	.07	.4	.1	.57
Company B	.03	.3	.1	.43
Total	.1	.7	.2	1

What is the probability that a randomly selected US job was neither eliminated by Company B nor eliminated because of outsourcing?

B. An Ear, Nose and Throat (ENT) medical practice collected information on 200 patients who had throat illnesses the previous year. The study investigated whether the cause of their illnesses was either bacterial or viral. The observed frequencies are shown in the following table.    

	Pharyngitis	Laryngitis	Total
Bacterial	29	37	66
Viral	46	88	134
Total	75	125	200

What is the probability that a randomly selected patient had a bacterial throat illness given that the patient had pharyngitis?

C. The following table summarizes the number of cavities of 600 elementary students who live in districts within the city that either fluoridate or do not fluoridate their water supply.    

Number of Cavities
	1	2	3	4	Total
Fluoridated	142	94	31	36	303
Non-Fluoridated	110	79	69	39	297
Total	252	173	100	75	600

What is the probability that a randomly selected student has 2 cavities given that he/she lives in a district with fluoridated water?

D. The accounting and human resource (HR) departments of a large company recently hired 35 new employees. The departments recorded how long it took newly hired employees to earn a raise. The data are summarized in the following frequency table.   

	6 months	12 months	18 months	24 months	Total
Accounting	3	5	10	4	22
HR	1	5	4	3	13
Total	4	10	14	7	35

What is the probability that a randomly selected new employee earned a raise in 6 months given that he/she works in the accounting department?

Please explain each step because Im very confused with all of it, thank you!

Answer 1