test #2 cheat sheet v2.5

# test #2 cheat sheet v2.5 - Ex There are 15 dogs entered in...

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Ex There are 15 dogs entered in a show. How many ways can first, second, and third place be awarded? N=15 R=3 15 P 3 15!/(13-3)!= 3,730 ways Combination of n objects taken r at a time - A selection of r objects from a group of n objects without regard to order n C r Ex There are 13 students in a club. How many ways can four students be selected to attend a conference? N=13 R=4 13 C 4 13!/(13-4)!(4!)= 715 ways Classical (theoretical) Probability - Each outcome in a sample space is equally likely Empirical (statistical) Probability - Based on observations obtained from probability experiments. The relative frequency of an event. 4! (4*3*2*1)=24 How many 4 letter TV call signs are possible, if each sign must start with either a K or W? 1 st letter=2 (K or W) 2 nd letter=26 3 rd letter=26 4 th letter=26 2*26*26*26=35,152 possibilities. Chapter 3 Review problems Ex On the basis of prior counts, a quality control officer says there is a 0.05 probability that a randomly chosen part is defective. Empirical probability Ex The probability of randomly selecting five cards of the same suit (a flush) from a standard deck is about 0.0005. Classical Ex The chance that corp A’s stock price will fall today is 75%. Subjective Probability Ex The probability of rolling 2 six-sided dice and getting a sum greater than nine is 1/6. Classical probability #of employees 0-4 5-9 10-19 20-99 100 + Percent of firms 60.8% 17.7 % 10.8 % 8.9% 1.8 % Ex What is the probability that a randomly selected firm will have at least 10 employees? P (at least 10) =0.108+0.089+0.018= 0.215 Ex What is the probability that a randomly selected firm will have fewer than 20 employees? P (less than 20)= .608+.177+.108= .893 Ex Tossing a coin four times, getting four heads, and tossing it a fifth time and getting a head. Independent. The first event doesn’t affect the outcome of the second event. Ex Taking a driver’s education course and passing the drivers license exam. Dependant. You have to take the course to pass the exam. Ex You are shopping, and your roommate has asked you to pick up toothpaste and dental rinse. However, your roommate did not tell you which brands to get. The store has 8 brands of toothpaste and 5 brands of dental rinse. What is the probability that you will purchase the correct brands of both products ? P (correct toothpaste and dental rinse) = P (correct toothpaste) * P (correct dental rinse) =(1/8)*(1/5)= 0.025 Ex Event A: Randomly selecting a red jelly bean from a jar. Event B: Randomly selecting a yellow jelly bean from the same jar. Mutually exclusive because both events cannot occur at the same time. Ex

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test #2 cheat sheet v2.5 - Ex There are 15 dogs entered in...

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