Solutions to Exercises

Solution to Exercise 1
a.
i. 71
ii. 3
iii. 2.8
iv. 48
v. 47
c. N (71, \dfrac{3}{\sqrt{48}})
d.
i. CI: (70.15,71.85)
iii. EB = 0.85


Solution to Exercise 2
a.
i. 8629
ii. 6944
iii. 35
iv. 34
C. t34
d.
i. CI: (6243, 11,014)
iii. EB = 2385
e. It will become smaller


Solution to Exercise 3
a.
i. 8
ii. 4
iii. 81
iv. 80
c. t80
d.
i. CI: (7.12, 8.88)
iii. EB = 0.88


Solution to Exercise 4
a.
i. 2
ii. 0.1
iii. 0.12
iv. 16
v. 15
b. the weight of 1 small bag of candies
c. the average weight of 16 small bags of candies
d. N (2, \dfrac{0.1}{\sqrt{16}})
e.
i. CI: (1.96, 2.04)
iii. EB = 0.04
f.
i. CI: (1.94, 2.06)
iii. EB = 0.06


Solution to Exercise 5
a.
i. 6
ii. 3
iii. 14
iv. 13
b. the time for a child to remove his training wheels
c. the average time for 14 children to remove their training wheels.
d. t13
e.
i. CI: (3.58, 8.42)
iii. EB = 2.42


Solution to Exercise 6
a.
i. 320
ii . 400
iii. 0.80
c. N (0.80, \sqrt{\dfrac{(0.80)(0.20)}{400}})
d.
i. CI: (0.76, 0.84)
iii. EB = 0.04


Solution to Exercise 7
b. N (0.86, \sqrt{\dfrac{(0.86)(0.14)}{323}})
c.
i. CI: (0.59, 0.63)
iii. EB = 0.02


Solution to Exercise 8
a.
i. 7.9
ii. 2.5
iii. 2.8
iv. 20
v. 19
c. N (7.9, \dfrac{2.5}{\sqrt{20}})
d.
i. CI: (6.98, 8.82)
iii. EB:0.92


Solution to Exercise 9
a. t83
b. average cost of 84 used cars
c.
i. CI: (5740.10, 7109.90)
iii. EB = 684.90


Solution to Exercise 10
C