Answer:
Stratified sampling
Step-by-step explanation:
Samples may be classified as:
Convenient: Sample drawn from a conveniently available pool.
Random: Basically, put all the options into a hat and drawn some of them.
Systematic: Every kth element is taken. For example, you want to survey something on the street, you interview every 5th person, for example.
Cluster: Divides population into groups, called clusters, and each element in the cluster is surveyed.
Stratified: Also divides the population into groups. However, then only some elements of the group are surveyed.
In this question:
Population divided into groups, and random samples are drawn from the groups. This is a mark of stratified sampling.
Answer:
Proportion of the trees will have diameters between 2 and 6 inches = 0.8164
Step-by-step explanation:
Given -
Mean 
= 4
Standard deviation 
= 1.5
Let X be the diameter of tree
proportion of the trees will have diameters between 2 and 6 inches =
= 
= 
Put [
]
= 
= 
= .9082 - .0918
= 0.8164
This question is incomplete
Complete Question
Mr Sampson fills the family pool with water for the summer.After two hours,the water has reached a depth of 2.5 feet. After three hours,the water level has risen to 3 3/4 feet.If the relationship between time and water depth is proportional,what is the constant of proportionality?
Answer:
1.33
Step-by-step explanation:
Time is proportional to Depth
Hence:
T ∝ D
T = kD
Where k is the constant of proportionality
After two hours,the water has reached a depth of 2.5 feet. After three hours,the water level has risen to 3 3/4 feet.
Total number of hours now is 3 + 2 = 5 hours
5 = k × 3 3/4
5 = k × 3.75
k = 5/3.75
k = 1.33
The reference angle is
pi/3.
At 180 it would be 9pi/3 so going past that is 10pi/3.
