Statistics, Significance Testing And Different Types Of Tests

Question 1

What are descriptive statistics? And give three examples

Answer 1

Statistics in which frequency distribution or relations between variables are described
Examples: mean, median & mode

Question 2

What are inferential statistics? And what is the other name for inferential statistics?

Answer 2

Also known as inductive statistics, is the body of knowledge that deals with tests of significance

Question 3

What are tests of statistical significance

Answer 3

Techniques that help us to generalize a larger group
A class of statistical computations that indicate the likelihood that the relationship observed between variables in a sample can be attributed to sampling error only

Question 4

What are the three levels of significance?

Answer 4

0.5,0.1 and 0.001 ( 5/100, 1/100, 1/1000)

Question 5

What is the null hypothesis?

Answer 5

A statement claiming that two variables in the population are unrelated

Question 6

What is the alternative hypothesis?

Answer 6

A statement claiming that two variables are related

Question 7

What is the fallacy of affirming the consequent?

Answer 7

A principle of logic that suggests that the only way to “prove” or validate the alternative or research hypothesis is to demonstrate that the null is untrue

Question 8

What are the steps in significance testing?

Answer 8

1. Null and alternative hypothesis
2. Test statistic
3. p-value
4. Decision

Question 9

Explain what happens in the null and alternative step

Answer 9

Convert the research question into null and alternative hypotheses

Question 10

Explain what happens in the test statistic step and State the formula

Answer 10

Calculating the Z statistic from the data (a= x-xbar /s)

Question 11

Explain what happens in the P value step

Answer 11

The test statistic is converted into a conditional probability called the p-value

Question 12

Define the p-value

Answer 12

A measure of the probability that a difference between groups during research happened by chance which is calculated from observed data

Question 13

What happens in the decision step

Answer 13

If p< alpha the null is rejected ; otherwise accept the null hypothesis for lack of supporting evidence

Question 14

Differentiate between a directional and non-directional hypothesis

Answer 14

A directional hypothesis specifies the direction of the effect of the independent variable on the dependent variable
A non-directional hypothesis does not specify the direction of the effect of the independent variable on the dependent variable

Question 15

What do positive and negative z-scores mean?

Answer 15

A positive z-score means that the original score was above the mean
A negative z-score means that the original score was below the mean

Question 16

What is a one sample z-test?

Answer 16

A test of significance that can be performed when we know the population’s standard deviation as well as its mean

Question 17

What is a one sample t-test?

Answer 17

A test that can be performed when we know the population’s mean but not its standard deviation

Question 18

What is a one sample test?

Answer 18

Tests that can compare data from a sample of similar data in a population

Question 19

What is a t-test?

Answer 19

A test of significance similar to the z-test but used when the population’s standard deviation is unknown

Question 20

When should a t-test for a single sample be used?

Answer 20

When the mean of a sample is compared to the mean of the population

Question 21

When should a two sample t-test be used?

Answer 21

When you have two groups or two sets of data and you wish to compare the mean scores

Question 22

Differentiate between type 1 and type 2 errors

Answer 22

Type 1: probability of falsely rejecting a true null hypothesis when it is true - false positive
type 2: the incorrect retaining of a false null hypothesis - false negative

Question 23

Why is it important to avoid type 1 errors?

Answer 23

Because it we do not, the research will be flawed and can have potentially fatal mistakes