7.1

31.

shadenorm(mu = 62, sig = 18, below = 44, col = "blue", dens = 200)

Interpretation 1. 15. 87% of the cell phone in the U.S. are less then $44 per month.

Interpretation 2. The probability is 0.1587 that a randomly selected cell phone plan in the U.S. is less than $44 per month. 32.

shadenorm(mu = 14, sig = 2.5, above = 17, col = "blue", dens = 200)

Interpretation 1. 11.51% of refrigerators are kept for 17 years.

Interpretation 2. The probability is 0.1151 that a randomy selected refrigerator is more than 17 years old.

33.

shadenorm(mu = 3400, sig = 505, above = 4410, col = "blue", dens=200)

Interpretation 1. 2.28% of full term babies have a birth weight of more than 4410 grams.

Interpretation 2. The probability is 0.0228 that the birth weight of a randomly chosen full term baby is more than 4410 grams.

34.

shadenorm(mu = 55.9, sig = 5.7, below = 46.5, col = "blue", dens=200)

Interpretation 1. The proportion of 10-year-old males are less than 46.5 inches tall is 0.0496.

Interpretation 2. The probability that randomly selected 10 years old male is less than 46.5 inches tall is 0.0496.

35.

Interpretation 1. The proportion of human pregancies that last more than 280 days is 0.1908

Interpretation 2. The probability that a randomly selected human pregancy that last more than 280 days is 0.1908

Interpretation 1 The proportion of human pregancies that last between 230 and 260 days is 0.3416.

Interpretation 2. The probability that a randomly selected human pregancy that last between 230 and 260 days is 0.3416.

36.

Interpretation 1. The proportion of times that Elena gets more than 26 miles per gallon is 0.3309.

Interpretation 2. The probability that a randomly selected fill-up yields at least 26 miles per gallon is 0.3309.

Interpretation 1. The proportion of times that Elena gets between 18 and 21 miles per gallon is 0.1107.

Interpretation 2. The probability that a randomly selected fill-up yields between 18 and 21 miles per gallon is 0.1107.

7.2

5.

  1. 0.0071
  2. 0.3336
  3. 0.9115
  4. 0.9998

7.

  1. 0.9987
  2. 0.9441
  3. 0.0375
  4. 0.0009

9.

  1. 0.9586
  2. 0.2088
  3. 0.8479

11.

  1. 0.0456
  2. 0.0646
  3. 0.5203

13. -1.28

15. 0.67

17. -2.575 and 2.575

33. 40.62

35. 56.16

37.

shadenorm(mu = 21, sig = 1.0, below = -1000, col = "blue", dens=200)

  1. 0.1587. If 100 eggs are randomly selected, we would expect amlost 16 to incubate in less than 20 days.
  2. 0.1587. If 100 eggs are randomly selected, we would expect 16 to incubate in more than 22 days.
  3. 0.4772. If 100 eggs are randomly selected, we would exepct almost around 48 to incubate in between 19 and 21 days.
  4. yes it will be usual. P(x<18)=0.0013.

39.

  1. 0.8658
  2. 0.0132
  3. 0.7019
  4. 0.1230
  5. 96 percentile
  6. 4 percentile

41.

  1. 0.4013
  2. 0.1587
  3. 0.7590
  4. 0.1894
  5. 0.0951
  6. yes, 0.0043

43.

  1. 0.0764
  2. 0.0324
  3. 162
  4. 11804

45.

  1. 0.3228
  2. yes

47.

  1. 20 days
  2. 19-23 days

56. SAT