Ch. 6.1 #7-49 odd

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28. Bottled Drinking Water Americans drank an average of 23.2 gallons of bottled water per capita in 2004. If the standard deviation is 2.7 gallons and the variable is normally distributed, find the probability that a randomly selected American drank more than 25 gallons of bottled water. What is the probability that the selected person drank between 18 and 26 gallons? 23.2, 2.7 For x 25 gallons: 25 23.2 z 0.67; the corresponding area=0.7486 2.7 Pz ( 0.67) 1 0.7486 0.2514 0.67 For 18 x 26gallons: 18 23.2 z 1.93; the corresponding area=0.0268 2.7 26 23.2 z 1.04; the corresponding area=0.8508 2.7 P(18 x1.04) 0.8508 0.0268 = 0.824 -1.93 1.04 30. Security Officer Stress Tolerance to qualify for security officers’ training, recruits is tested for stress tolerance. The scores are normally distributed, with a mean of 62 and a standard deviation of 8. If only the top 15% of recruits are selected, find the cutoff score. 62, 8 10.15 0.85 The corresponding z score is 1.04 Cutoff z 1.048 62 70.32 6.3 #9, 13, 15, 17, 21, 23 9. College Costs The mean undergraduate cost for tuition, fees, room, and board for four-year institutions was $26,489 for the 2004–2005 academic year. Suppose that σ =$3204 and that 36 four-year institutions are randomly selected. Find the probability that the sample mean cost for these 36 schools is a. Less than $25,000 µ=26,489, n=36, σ= 3204, P( x < 25.000)
x x 25,000 26,489 Z 2.79 3204 n 36 P( z < -2.79)=0.0026 -2.97 b. Greater than $26,000 µ=26,489, n=36, σ= 3204, P( x >26.000) Z x x 26,000 26,489 0.92 3204 n 36 -0.92 P( z > -0.92)=1-0.1788 = 0.8212 c. Between $24,000 and $26,000. µ=26,489, n=36, σ= 3204, P($24,000 < x
Page 1 and 2: Ch. 6.1 #7-49 odd The area is found
Page 3 and 4: The area is found by looking up z=
Page 5 and 6: Area= 0.9591 - 0.0069 = 0.9522 Area
Page 7 and 8: c) 60.64% of the area under the dis
Page 9 and 10: . More than $40,000 a year X 40,00
Page 11 and 12: 15. Waiting to Be Seated The averag
Page 13: Therefore, a cutoff score of 93 wil
Page 17 and 18: Pz ( 0.90) 1 0.8159 0.1841 18.41%
Page 19 and 20: q = 1-q = 1 - 0.6 = 0.4 np = (10)(0
Page 21: 11. Elementary School Teachers Wome

Ch. 6.1 #7-49 odd

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