Question

menstulle proves all be m e on this sheet in hard copy at the start of Tuesday's class. 1. Using the unit normal table, find the following: (2 points) a. p(2.25) b. P(Z >-75) c. the z score for 40% in the tail on the right d. the two z scores that determine the interquartile range (25h and 75 percentiles) 2. Suppose that mean annual rainfall in a region is 36" with a standard deviation of 10", 48" and higher is associated with flood activity, and 20" or lower is considered a drought. In what percent of years (total) can either drought OR flood conditions be expected? Please show your work-and drawing a normal distribution will help! (3 points) D. Focus RO

Answer 1

a). plz > 0.25) = 1-plz <0.25)

  

=1-0.5987=0.4013

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b) plz > -0.75) = p(2 <0.75) = 0.7734

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c). pz > 20) = 0.40

1 - plz <20) = 0.40

  

plz < 0) = 0.60

  

zo = 0.2533

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d) p(2 <20) = 0.25

zo = -0.674

  

plz < 0) = 0.75

zo = 0.674

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