Flashcards in Chapter 5- Sampling and Probability Deck (27):

1

## What is random sampling?

### Random sampling is one in which every member of the population has an equal chance of being selected into the study. Ideal and more likely to lead a representative sample. Expensive and difficult to achieve

2

## What is convenience sampling?

### Convenience sampling is one that uses participants who are readily available. Less expensive and easier than random sampling. Used most often.

3

## What is generalizability?

### Generalizability is the researchers ability to apply findings from one sample or in one context to other samples or contexts. Also called External Validity

4

## Explain the external validity principle

### If you don't have sufficient gernalizability, you can never be certain that results from your sample apply to the larger population.

5

## What is the goal of samples?

### The goal of samples is to create a sample that represents our population of interest

6

## What is independent sampling?

### Independent sampling means each person selected had no influence over other people selected

7

## If sampling is not random and independent, what can happen?

### Resulting sample may be biased

8

## What is the difference between random sampling and random assignment?

### Random sampling is the method participants are assigned to a sample; Random assignment is the method which individuals within a sample are assigned to a condition.

9

## What is a convenience sample?

### Convenience sample consist of participants who are readily available. Convenience samples may not be generalizable to population. This method of sampling is used very often in social sciences.

10

## What is a volunteer sample?

### Volunteer sample is when participants self-select themselves to be in a sample. Like convenience, they may not be generalizable to population

11

## What is replication?

### Replication is doing the study again with different samples.

12

## What is a sampling error?

### A sampling error is the discrepancy of what the sample looks like versus what the population looks like.

13

## What are inferential statistics?

### Inferential statistics utilizes sample data to generalize to larger population. This is done by using probabilities.

14

## What is probability?

### Probability is the likelihood something will occur out of all possible outcomes

15

## Why should we care about probabilities?

### Probability theory helps us determine how likely are sample results are to occur given a hypothesis. Nothing is for certain and to make a conclusion

16

## What is personal probability?

### Personal probability is the likelihood something will occur based on one's opinion. Subjective

17

## What is expected relative-frequency probability?

### Expected Relative frequency probability is the likelihood that an event will occur in the long run. A proportion of times the event occurs after many trials

18

## What is a trial?

### A trial is each time a procedure occurs

19

## What is an outcome?

### An outcome is the result of the trial

20

## What is success?

### Success is when the outcome you were interested in occurs

21

## What is the law of large numbers?

### The law of large numbers is as the numbers of the trials increase, our observed probability will approach the expected relative frequency probability

22

## Describe probability vs. proportion vs. percentage

### Probability is the long term proportion; Proportion is the success divided by the total trials; Percentage is the probability or proportion multiplied by 100

23

## Individual trials must be independent. Explain this.

### Independent means the outcome of each trial must not depend in any way on the outcome of previous trials. Each trial is independent from other trials

24

## What are 2 types of errors that can occur?

### Type 1 and Type 2

25

## What is Type 1 error and Type 2 error?

### The easiest way to think about Type 1 and Type 2 errors is in relation to medical tests. A type 1 error is where the person doesn't have the disease, but the test says they do (false positive- REJECT THE NULL). A type 2 error is where the person has the disease but the test doesn't pick it up (false negative- FAIL TO REJECT THE NULL).

26

## What is the null hypothesis?

### Null hypothesis- it proposes that nothing will happen--nothing is going on.

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