Basic Applied Statistics 200
Solutions to Quiz 4 Feb 2012

1.  
   1. (i) [Its values are the quantities 0 to 5.]
   2. "at least one" means anything but zero: probability is 1-0.12=0.88
   3. 0.18 + 0.07 = 0.25
   4. 0.12(0.12)=0.0144
2.  
   1. intersection of Pitt row and Passed column has 152 individuals [Notice that I asked "How many..." not "What is the probability..."]
   2. 152+29+157=338 [Again, I asked for a count, not a probability.]
   3. 309/372=0.83
   4. 152/181=0.84
3.  
   1. (iv) [Notice that the variable's values extend roughly from 0 to 50. If the mean is about 25, all values are within 2 or 3 times 9.4 of the mean. Also, 2.9 is too small and 29 is too large.]
   2. (v) because the relationship is weak and positive. Also, 0.27 is the positive square root of 0.075, the value of R-Sq as a decimal.
   3. (ii)
   4. 7.209 (S)
   5. 20.1+0.211(50)=30.65 [Some people plugged 0.50 into the line instead of 50. Refer to the horizontal axis to confirm that 0.50 doesn't represent 50 percent.]
   6. 0.211 [This is what the slope tells us.]
   7. (ii)
   8. (ii)

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