Question

Based on the data in the two-way table, the probability of being older than 25 years and having a hemoglobin level above 11 is
A:0.29
B:0.34
C:0.54

The probability of having a hemoglobin level above 11 is .
A:0.25
B:0.3
C:0.36

Being older than 25 years and having a hemoglobin level above 11
A.are
B.are not
dependent on each other.

20 points :3

Answer 1

Based on the data in the two-way table, the probability of being older than 25 years and having a hemoglobin level above 11 is
(154-69)/(429-139)
=85/290
=0.2931~0.29
Answer: A. 0.29

The probability of having a hemoglobin level above 11 is 
P(H>11)
=154/429
=0.35897~0.36
Answer: C:0.36


Being older than 25 years and having a hemoglobin level above 11 
Are not dependent on each other because w have not been told about any factors that were included in selection of sample. 
Answer: B.are not

Answer 2

Answer:

A) 0.29; C) 0.36; A) are

Step-by-step explanation:

There are a total of 128+162 = 290 people that are over 25 years old.  Out of these, there are 84 people with a hemoglobin level above 11; this is a probability of 84/290 = 0.29.

There are 154 people with a hemoglobin level over 11 out of 429 people total; 154/429 = 0.36.

In order for two events to be independent,

P(A∩B) = P(A)·P(B)

The probability that someone is over 25 and has a hemoglobin level above 11 was 0.29.

The probability that someone is over 25 is 290/429; the probability that someone has a hemoglobin level above 11 is 154/429.  This makes

P(A)·P(B) = (290/429)·(154/429) = 0.24

The probabilities are not equal, so the events are not independent; this means they are dependent.