7.1

31.

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

Interpretation 1.15.87 % of cell phone plans in US are less than 44$ per month.

Interpretation 2. The probabality if less than $44 per month is 0.1587.

32.

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

Interpretation 1. 11.51% of refridgetors will last more than 17 years

Interpretation 2. The proabability of a fridge lasting longer in 0.1151

33.

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

Interpretation 1. 2.28% of full term babies wiegh more htan 4,410 g.

Interpretation 2.The probability of a full term baby weighing more than 4,410 g is .0228

34.

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

Interpretation 1. 4.96% of 10 year old males are less than 46.5 inches tall

Interpretation 2. The proability of a 10 year man being less than 46.5 inches tall is .0496

35.

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

Interpretation 2. .1908 is the probability that a pregnanacy will last longer than 280 days

Interpretation 1.34.16% of human pregancies last between 230-260 days

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

36.

Interpretation 1. 33.09% of the time the mpg will be greater than 26

Interpretation 2. .3309 is the proabability that the mpg will be greater than 26

Interpretation 1. 11.07 % of the time the mpg between 18-21

Interpretation 2. .1107 is the probabilty the mpg will be bewteeen 18-21

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. 0.8479

11.

  1. 0.0456
  2. .0646
  3. .5203

13. z=-1.25

15. z= .67

17. z= -2.575 z = 2.575

33. x= 40.62

35. x= 56.16

37.

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

  1. P(x<20 ) = .1587
  2. P(x>22) = .1587
  3. P(19 </=X </= 21) =.4772

  4. Yes; P(x < 18) =.0013 39.

  5. P (1000 </= x </= 1400) =.8658
  6. P(X<1000) = .0132
  7. .7019 of the bags have fewer than 1200 chocolate chips
  8. .1230 of the bags have fewer than 1125 chocolate chips
  9. A bag with 1475 chocolate chips is the 96th percentile

  10. A bag with 1050 chocolate chips is the 4th percentile

41.

(a).4013 of pregancies last more than 270 days (b) .1587 of pregnancies last less than 240 days (c) .7590 of pregnancies last between 240 and 280 days (d) P (x> 280) =.1894 (e) P (x </= 245) = .0951 (f) yes .0043 births are preterm

43.

  1. .0764 of the rods have a length of less than 24.9cm
  2. .0324 of the rods will be discarded
  3. The manager expects to discard 162/500 of the rods
  4. The manager should make 11,804 rods

45.

  1. the favored team will win or lose the same amount , a mean of 0 means that the spreads are accurate
  2. P(x >/=5) = .3328
  3. p(x</=-2) = .4286

47.

  1. the 17th percentile is 20 days
  2. From 19 days to 23 make up the middle 95%

56. You would do better on the SAT because the z-score for the ACT was .9607,falling in the 83rd percentile with the SAT z-score was 1.019, falling in the 85th percentile.