First, let's break down what the difference between a sample and population is. A sample is a small part or quantity intended to show what the whole is like. A population is all inhabitants of a town, country, or the world. Samples are only representative of the population if the data collected is being collected in a fair manner. In answer choices A - C, the researcher is collecting data in locations specific to what is being studied. The outcome is likely to be bias because of the method in which the data is being collected. It is for that reason that the correct answer is D. To learn how many students at her school spend more than $10 on books in a month, Mia speaks to every sixth student she meets in the school hallway.
Answer:
The first one
Step-by-step explanation:
Answer:
8 units
Step-by-step explanation:
b(14)/2 = 56
14b = 112
b = 8 units
Answer:
The probability that they purchased a green or a gray sweater is 
Step-by-step explanation:
Probability is the greater or lesser possibility of a certain event occurring. In other words, probability establishes a relationship between the number of favorable events and the total number of possible events. Then, the probability of any event A is defined as the quotient between the number of favorable cases (number of cases in which event A may or may not occur) and the total number of possible cases. This is called Laplace's Law.

The addition rule is used when you want to know the probability that 2 or more events will occur. The addition rule or addition rule states that if we have an event A and an event B, the probability of event A or event B occurring is calculated as follows:
P(A∪B)= P(A) + P(B) - P(A∩B)
Where:
P (A): probability of event A occurring.
P (B): probability that event B occurs.
P (A⋃B): probability that event A or event B occurs.
P (A⋂B): probability of event A and event B occurring at the same time.
Mutually exclusive events are things that cannot happen at the same time. Then P (A⋂B) = 0. So, P(A∪B)= P(A) + P(B)
In this case, being:
- P(A)= the probability that they purchased a green sweater
- P(B)= the probability that they purchased a gray sweater
- Mutually exclusive events
You know:
- 8 purchased green sweaters
- 4 purchased gray sweaters
- number of possible cases= 12 + 8 + 4+ 7= 21
So:
Then:
P(A∪B)= P(A) + P(B)
P(A∪B)= 
P(A∪B)= 
<u><em>The probability that they purchased a green or a gray sweater is </em></u>
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Answer:
josh vendió 17 libros recaudando 306 dolares .
jessica vendió 255 libros recaudando 4590 dolares.
Step-by-step explanation:
Sustituimos por variables :
libros que vendió Jessica = x
libros que vendió Josh = y
entonces:
x + y = 272
Jessica vendió 15 veces mas libros que josh:
x = 15y
Reemplazamos en la anteriior ecuacion:
15y +y = 272
16y = 272
y = 17
Reemplazamos en la primela ecuacion :
x + 17 = 272
x = 255