7.1

31.

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

Interpretation 1. 15.87% of monthly charges for cell phone plans in the United States is less than $44

Interpretation 2. 84.13% of monthly charges for cell phone plans in the United States is more than $44

32.

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

Interpretation 1. 11.51% of refrigerator lifespans are above 17 years

Interpretation 2. 88.49% of refrigerator lifespans are below 17 years

33.

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

Interpretation 1. 2.28% of baby’s birth weight are above 4410 grams

Interpretation 2. 97.72% of baby’s birth weight are below 4410 grams

34.

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

Interpretation 1. 4.96% of 10-year-old males heights are below 46.5 inches

Interpretation 2. 95.04% of 10-year-old males heights are above 46.5 inches

35.

Interpretation 1. 19.08% of human pregnancies length are above 280 days

Interpretation 2. 80.92% of human pregnancies length are below 280 days

Interpretation 1.34.16% of human pregnancies length are above 230 days and below 260 days

Interpretation 2. 65.84% of human pregnancies length are below 230 days and above 260 days

36.

Interpretation 1. 33.09% of miles gotten per hour were above 26

Interpretation 2. 66.91% of miles gotten per hour were below 26

Interpretation 1. 11.07% of miles gotten per hour are above 18 and below 21

Interpretation 2. 88.93% of miles gotten per hour are below 18 and above 21

7.2

5.

  1. .0071
  2. .3336
  3. .9115
  4. .9998

7.

  1. .9987
  2. .9441
  3. .0375
  4. .0009

9.

  1. .9586
  2. .2088
  3. .8479

11.

  1. .0456
  2. .0646
  3. .5203

13. -1.28

15. -.84

17. -2.57, 2.57

33. -1.34. * 7 + 50 = 40.62

35. .88. * 7 + 50 = 56.16

37.

  1. z = -1.00 = 0.1587
  2. z = 1.00 = 0.8413 = 1 - 0.8413 = 0.1587
  3. 19 = -2.00. 21 = 0. -2.00 = 0.0228. 0 = 0.5000. .5000 - .0228 = 0.4772
  4. It’s so far from the mean that it is highly unusual. If a egg hatched that early it brings up questions of how it was treated beforehand.

39.

  1. -2.22, 1.17. .0132, .8790, = .8658 = 86.58%
  2. -2.22, .0132 = 1.32%
  3. -0.53, 1-.2981 = .7019 = 70.19%
  4. -1.16, .1230 = 12.30%
  5. 1.805. .9678 = 96.78%
  6. -1.797. .0367 = 3.67%

41.

  1. .25, .5987. 1-.5987 = .4013 = 40.13%
  2. -1, .1587 = 15.87%
  3. -1.625, .875. 59.9%-8.1% = 51.8%
  4. .88, .8106. 1 - .8106 = .1894 = 18.94%
  5. -1.31. .0951 = 9.51%
  6. -2.625. Very, as they hit only .44% of births

43.

  1. z = -1.43. the proportion of steel rods less than 24.9 cm is .0764
  2. z = +- 2.14. .0162 * 2 = .0324
  3. 5000(.0324)=162
  4. z=+-1.43. .0764 * 2 = .1528. 1-.1528 = .8472. 10000/.8472 = 11803

45.

  1. .46
  2. -.18
  3. No, at 0, it’s a 50-50 chance that the team would beat the point’s spread.

47.

  1. z=-.95. x = (-.95)(1) + 21 = 20.05 days
  2. 1-.95/2 = .05. +-1.64. x = (-1.64)(1) + 21 = 19.36 days x = (1.64)(1) + 21 = 22.64 days

56. ACT 21.1 5.1 SAT 1026 210 26 = .96 1240 = 1.02 I did better on the SAT overall as my z-score is a little higher then the ACT.