Answer:
34.134%
68.268%
Step-by-step explanation:
Given that:
Mean (m) = 500
Standard deviation (s) = 100
Percentage between 500 and 600
P(500 < x < 600)
P(x < 600) - P(x < 500)
Z = (x - m) / s
P(x < 600)
Z = (600 - 500) /100 = 1
P(x < 500)
Z = (500 - 500) / 500 = 0
P(Z< 1) - P(Z < 0)
0.84134 - 0.5
= 0.34134
= 0.34134 * 100%
= 34.134%
B.) Between 400 and 600
P(x < 400)
Z = (400 - 500) /100 = - 1
P(x < 600)
Z = (600 - 500) / 500 = 1
P(Z< 1 ) - P(Z < - 1)
0.84134 - 0.15866
= 0.68268
= 0.68268 * 100%
= 68.268%
Answer:
15
Step-by-step explanation:
First blank: not random Because he sent it to the top 5 students. Not random students throughout the grade.
second blank: I would guess not valid because it was not a random sample.
