Answer:
The number of different combinations of three students that are possible is 35.
Step-by-step explanation:
Given that three out of seven students in the cafeteria line are chosen to answer a survey question.
The number of different combinations of three students that are possible is given as:
7C3 (read as 7 Combination 3)
xCy (x Combination y) is defines as
x!/(x-y)!y!
Where x! is read as x - factorial or factorial-x, and is defined as
x(x-1)(x-2)(x-3)...2×1.
Now,
7C3 = 7!/(7 - 3)!3!
= 7!/4!3!
= (7×6×5×4×3×2×1)/(4×3×2×1)(3×2×1)
= (7×6×5)/(3×2×1)
= 7×5
= 35
Therefore, the number of different combinations of three students that are possible is 35.
Since y=mx+b is the slope-intercept form of a line, where m=slope and b=y-intercept, we can see that:
The y-intercept is 5 (technically the point (0,5))
The x-intercept occurs when y=0 so:
2x+5=0
2x=5
x=2.5
So the x-intercept is the point (2.5, 0)
The answer would be: <span>99.0%
</span>
The disease is rare with a prevalence of <span>one out of every thousand people have it. That means, the chance of Roberto has the disease without any test would be 1/1000 or 0.1%
The test sensitivity is 99%, which mean 99% of people with positive test result would have the disease. The chance is should not be influenced by the disease prevalence. </span>
Answer:
Step-by-step explanation:
Hello!
In stratified sampling, the researcher separates the population into subgroups according to the criteria established for his experiment. These subgroups will be made up of homogeneous observation units in terms of the characteristics of interest. In this case, each of the people who make up the groups will have only one of the two possible opinions (support, do not support) but not both.
When this type of sampling is performed, it is the researcher who decides what sample size you want to take, depending on various economic factors, availability of materials, access to experimental units (for example, if they are endangered animals, that is, finite populations , you cannot take very large sample sizes)
You can perform a proportionate stratified sampling and take a proportion of people who answered "yes" and a proportion of people who answered "no."
In this type of sampling, when taking a given proportion of each population, it is easier to extrapolate the results obtained to the populations. Then, if for example you must take a sample of size n = 20 where both strata correspond to half, that is to say that the stratum corresponding to "yes" will be 10 people and the stratum corresponding to "no" will be ten people.
I hope this helps!
