Science Ch.1, Lesson 2

Which size sample would better represent an entire population? small, medium, or large?

A large sample would best represent an entire population.

What is a hypothesis?

A possible answer to the question written using an "if, then, because" statement; it must be testable

Why should a scientist test only one variable at a time?

If there is more than one variable, you cannot be sure which one caused the results of the experiment.

Do scientists use all the steps in the scientific method during every investigation?

No, they do not always use all the steps.

Why do scientists use models to study things that are very large, have many parts, or are difficult to observe directly?

Scientists can handle and observe a model more easily than the actual object or concept.

Why do scientists use sampling in their investigations?

Sometimes an entire population cannot be tested.

Why do scientists use repeated trials?

They want to make sure their conclusions are valid. (true/correct)

Can the models scientists use test differently from real life examples?

Yes, models can behave differently from real life objects.

What are 4 investigations a scientist can design to test a hypothesis?

a controlled experiment, a survey, a sample, and a model

sample

a small, random group of a population which is tested; the results of these tests are then applied or generalized to the entire population

What is a control group?

a standard against which change is measured; the group you use for comparison

hypothesis

a statement of what a scientist thinks will happen during an investigation

model

an idea or object that represents another thing

What is the first step in a scientific investigation?

ask a question or state a problem

In what ways can surveys can be conducted?

face to face, by phone, by questionnaire, online

What are scientific methods?

organized ways to answer questions or solve problems

survey

questionnaires given to a number of people whose answers are recorded and then analyzed; used to gather information which helps people make decisions about topics of interest

variable

something that can change during a scientific investigation

experiment

the use of scientific methods to test a hypothesis

census

when you survey every member of a population or everyone in a group

How do scientific investigations usually start?

with an observation that brings up a question