Exam 2 Spring 2008 Practice Test for Spring 2009 1 You know that a nearby community is comprised of 60 Republicans 35 Democrats and 5 Independents You use this information to predict the number of votes each candidate will get at the next election This is an example of Probability or Statistics 2 You survey the Democrats to see if they prefer Obama or Clinton for their presidential nominee The 2 possible answers they can give Obama or Clinton are examples of Outcomes or Events 3 The survey described above is an example of binomial data True or False 4 You are a University of Maryland bus driver who has driven the same 8am route for a year Your supervisor asks you to estimate without looking at any data the probability that the bus will have more than 10 riders at 8am the next day This probability has been estimated 1 word 5 P A indicates a probability that was estimated 1 word 6 You doctor tells you that your risk for diabetes later in life is 1 in 10 What is the probability in percent that you will have diabetes 7 The complement of event A is the probability that the event will occur True or False 8 You survey people to determine the name of their favorite restaurant The data collected will be what type 2 words 9 You now survey people to determine whether they prefer deep dish pizza or regular crust pizza These data would be what type 1 or 2 words 10 Police report that 78 of drivers suspected of DWI are given a breath test 36 a blood test and 22 are given both a Are giving a DWI suspect a blood test and a breath test mutually exclusive Yes or no b Are giving a DWI suspect a blood test and a breath test independent Yes or no 11 The Masterfoods company reports that bags of Peanut Butter M M s contain 10 brown 10 red 20 yellow 20 blue and 20 orange the remaining candies are green If you pick one candy from a bag at random what is the probability that a It is green Given the information about candy color distribution now consider that you pick 4 M M s in a row What is the probability that b It is a primary color red yellow or blue c It is not orange d all 4 are blue e at least one is red f the fourth chosen is the first to be brown 12 A biology professor responds to student questions via e mail The data below describe the probability of receiving a certain number of emails in a day Emails received Probability 0 05 1 10 2 2 3 25 4 3 5 1 a On average how many emails would the professor expect to receive each day b Showing probability results in this way above is an example of Probability function or Probability Distribution c If the data were plotted as a histogram the data would be skewed left True or False 13 A survey of families revealed that 58 of families eat turkey at holiday meals 44 eat both turkey and ham a What is the probability that a family chosen at random had neither turkey nor ham at their holiday meal b What is the probability that a family chosen at random had ham given they also had turkey in the meal 14a In the US Population 22 of people are allergic to some type of pet If you randomly sampled 7 people what is the probability that you will find exactly 3 of the 7 are allergic to pets 14b If instead you randomly selected 100 people what is the probability that 20 or more of these people are allergic to pets 15 For the results of a survey you compare your o bserved values to those expected for the binomial distribution The data don t match Which of the following could be the reason the data do not follow a binomial distribution a distribution of observed values is not independent of one another b distribution of observed values are not truly random c distribution of observed values are biased in some way d any of the above results could explain why your observed values do not match the expected values 16 You collect 8 vegetables 5 are potatoes 3 are cucumbers You decide to line these vegetables in a row and realize there are many different combinations that could be created 5 potatoes first then the 3 cucumbers is one way 1 cucumber then 5 potatoes and then 2 cucumbers is another way How many possible different combinations could you create of 8 vegetables in a row if order is important Do not do this by hand there is an easier way 17 The distribution of every continuous variable follows a normal distribution True or False 18 Find the value of z for z 0 55 19 What is the value of z when the probability of a larger z value is 35 20 Bottles of True Value soda have a mean volume of 600 ml and a standard deviation of 5ml Assume soda volume is normally distributed a What is the probability that a bottle will be chosen at random and have a volume larger than 594 ml b What is the probability that a bottle is chosen at random and has a volume between 602 and 604 ml 21 If 40 percent of a normally distributed population of beetles have a weight greater than 45 grams and you know the population standard deviation is 4 grams what is the mean weight for this population of beetles