664 CHAPTER 11 Probability Example 4 Choosing One Bird from a List The names of 9 birds and their food preferences are listed in Table 11.3. Each of the 9 birds’ names is listed on a slip of paper, and the 9 slips are placed in a bag. One slip is to be randomly selected from the bag. Determine the probability that the slip contains the name of Now try Exercise 67 Table 11.3 Birds and Their Food Preferences Bird Peanut Kernels Cracked Corn Black-Striped Sunflower Seeds American goldfinch L L H Blue jay H M H Chickadee M L H Common grackle M H H Evening grosbeak L L H House finch M L H House sparrow L M M Mourning dove L M M Northern cardinal L L H Source: How to Attract Birds (Ortho Books) Note: = H high attractiveness; = M medium attractiveness; = L low attractiveness. Solution a) Two of the 9 birds listed are finches (American goldfinch and house finch). = P(finch) 2 9 b) One of the 9 birds listed has a high attractiveness to cracked corn (common grackle). = P(high attractiveness to cracked corn) 1 9 c) Reading across the rows reveals that 3 birds have a low attractiveness to peanut kernels, a low attractiveness to cracked corn, and a high attractiveness to blackstriped sunflower seeds (American goldfinch, evening grosbeak, and northern cardinal). ⎛ ⎝ ⎜ ⎞ ⎠ ⎟ = = P low attractiveness to peanuts, and low to corn, and high to black-striped sunflower seeds 3 9 1 3 d) Six birds have a medium attractiveness to either peanut kernels or to cracked corn (or both). They are the blue jay, chickadee, common grackle, house finch, house sparrow, and mourning dove. = = P(medium attractiveness to peanut kernels or cracked corn) 6 9 2 3 ■ Learning Catalytics Keyword: Angel-SOM-11.1 (See Preface for additional details.) a) a finch (any type listed). b) a bird that has a high attractiveness to cracked corn. c) a bird that has a low attractiveness to peanut kernels, and a low attractiveness to cracked corn, and a high attractiveness to black-striped sunflower seeds. d) a bird that has a medium attractiveness to either peanut kernels or cracked corn (or both). Davidtlam/Shutterstock
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