9. For a normal distribution with mean 20 and standard deviation 5, approximately what percent of
the observations will be between 5 and 35?
A. 50%
B. 68%
C. 95%
D. 99.7%

D. 99.7%

Step-by-step explanation:

Scores that lies within the first deviation(1σ) =

(20 - 5) to (20 + 5) → 15 to 25

Scores that lies within the second deviation(2σ) =

(20 - 5 - 5) to (20 + 5 + 5) → 10 to 30

Scores that lies within the third deviation(3σ) =

(20 - 5 - 5 - 5) to (20 + 5 + 5 + 5) → 5 to 35

As shown by the distribution graph below, 99.73% of the scores lies within the third deviation(3σ).

step-by-step explanation:

i found the life tables for the year 2012. 

life table of males at age 30. probability of dying between ages x and x+1

total population:  

29–30 . . . . . . . . . . . . 0.001030

30–31 . . . . . . . . . . . . 0.001061

males:  

29–30 . . . . . . . . . . . . 0.001420

30–31 . . . . . . . . . . . . 0.001448

white population

29–30 . . . . . . . . . . . . 0.001005

30–31 . . . . . . . . . . . . 0.001037

white males

29–30 . . . . . . . . . . . . 0.001372

30–31 . . . . . . . . . . . . 0.001399

non hispanic white population

29–30 . . . . . . . . . . . . 0.001083

30–31 . . . . . . . . . . . . 0.001116

non hispanic white males

29–30 . . . . . . . . . . . . 0.001477

30–31 . . . . . . . . . . . . 0.001503

jacob, non hispanic white male. 30 years old.

probability that jacob lives to be 30 years old. 

since the given probabilities are probabilities of dying, i think we simply subtract it from 1 to get the probability of living. we will use the probability of non hispanic white male.

                                          probability of living to be 30 y.o.

29 - 30 : 1 - 0.001477 = 0.998523

30 - 31 : 1 - 0.001503 = 0.998497