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.
Given:
Equilateral Triangular Prism
Each side of the triangular face has a length of 196cm
The tent is 250cm long
I have attached an image of the tent. Since the height of the tent is also the height of the triangle, I will solve for the height of the triangle using Pythagorean theorem.
I divided the equilateral triangle into 2 right triangle. The height then becomes the long leg of the triangle. The hypotenuse is 196cm and the short leg is 98cm, half of one side of the triangle.
a² + b² = c²
a² = c² - b²
a² = (196cm)² - (98cm)²
a² = 38,416cm² - 9,604cm²
a² = 28,812cm²
a = √28,812cm²
a = 169.74cm
The height of the tent is 169.74 centimeters.
Standard error of the mean is computed by:
Standard error = SD/ sqrt N
Where:
N is the sample size
SD is the standard deviation
To get the standard deviation, you need to get the sqrt of
the variance = sqrt 9 = 3
So plugging in our data:
Standard error = 3 / sqrt (16)
= 0.75
Answer: A
Step-by-step explanation:
If the fraction is negative, and the numerator and denominator is negative, then if you were to do anything to them it would become a positive