7.1

31.

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

Interpretation 1 the percentage of people who pay $44.00 a month or less is 15.87%.

Interpretation 2. therfore the probability that someone with a cell plan that is under $44.00 is .1587.

32.

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

Interpretation 1 11.51% of people in america have refrigerators that last for more than 17 years.

Interpretation 2. the probability that someone has a refrigeraftor that lasts more than 17 years is .1151.

33.

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

Interpretation 1.2.28% of all full term babies have birth wights more then 4410 grams .

Interpretation 2.the probability of a baby with a birthweight of more than 4410 grams being chosen randomly is .0228.

34.

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

Interpretation 1. the percentage of 10 year old males who are 46.5 inches in height or less is 4.96%.

Interpretation 2. The probability that a 10 year old male who is 46.5 inches or less would be chosen at random is .0496.

35.

Interpretation 1. 19.08% of pregnancies last longer than 280 days.

Interpretation 2. The probability that a pregnancy will last more than 280 days is .1908.

Interpretation 1.34.16% pregnancies last from 230-260 days

Interpretation 2. the probability that a pregnancy will last between 230-260 is .3416.

36.

Interpretation 1. the percentage of gas that last more than 26 miles is 33.09%

Interpretation 2. the probability that the gas will last more than 26 miles is 0.3309.

Interpretation 1. the percentage of miles pergalon that last between 18- 21 is 11.07%

Interpretation 2. The probability that the miles per gallon lasts between 18-21 is 0.1107.

7.2

5.

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

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. .67

17. -2.575, 2.575

33. 40.62 is at the 9th percentile

35. 56.16 is at the 81st percentile

37.

  1. .1587
  2. .1587
  3. .4772
  4. .0013 so about 1 egg in 1000hatches in less than 18 days.

39.

  1. 0.8658
  2. 0.0132
  3. 0.7019 of the bags have more than 1200 chocolate chips
  4. 0.1230 of the bags have fewer than 1125 chocolate chips
  5. a bag that contains 1475 chips is at the 96th percentile
  6. a bag that contains 1050 chips is at the 4th percentile

41.

  1. 0.4013 of pregnancies last more than 270 days
  2. 0.1587 of pregnancies last fewer than 250 days
  3. 0.75900 of pregnacies last between 240 - 280 days
  4. 0.1894
  5. 0.0951
  6. yea, 0.0043 of births are very preterm. so about 4 births in 1000 births are very preterm

43.

  1. 0.0764 of the rods have length of less than 24.9 cm
  2. 0.0324 of the rods will be discarded
  3. the plant manager excepts to discard 162 of the 5000 rods manufactured.
  4. to meet the order, the plant manager should manufacture 11,804 rods.

45.

  1. 0.3228
  2. 0.4286
  3. the favored team is equally likely to win or loose relative to the spread. yes, a mean of 0 implies the spreads are accurate.

47.

  1. the 17th percentile for incubation time is 20 days
  2. from 19 to 23 days make up the middle 95% of incubation times of the eggs.

56. he did better on the ACT