Hypothesis and probability FINAL

hypothesis

defined as a declarative statement that predicts the relationship between an independent variable and a dependent variable

• Null Hypothesis

• alternative hypothesis

• significance level

• conclusion

What are the 4 steps in hypothesis testing?

• Specify the ___

• Specify the ____

• Set the ____ level

• Draw a ____

null hypothesis (Ho)

this states that group means are not different (the groups come from the same population).

Researchers aim to disprove (reject) the null hypothesis

In research, do we try to prove or disprove the null hypothesis?

A patient outcome you want to improve (e.g., pain, function, walking speed)

in a physical therapy setting, what is typically the dependent variable?

"Reject" or "Do not reject" the null hypothesis.

What are the two possible decisions about a null hypothesis?

That we accept the alternative hypothesis.

What does rejecting the null hypothesis imply?

alternative hypothesis (H,)

type of hypothesis that is a statement that suggests a difference or relationship exists between groups or variables.

For patients with limited shoulder mobility, there will be no difference in mean change in ER between those who receive mobilization and those who do not

Example scenario: What is the null hypothesis for a study testing whether a single session of soft-tissue mobilization increases shoulder ER in patients with limited mobility?

Whether the patient received soft-tissue mobilization (yes vs. no).

What is the independent variable in the soft-tissue mobilization scenario?

External rotation (ER) range of motion improvement.

What is the dependent variable in the soft-tissue mobilization scenario?

alternative hypothesis

hypothesis type that is the statement that there is an effect or difference

The alternative hypothesis (Hy)

Which hypothesis does the researcher aim to support or prove?

both

Can the alternative hypothesis be directional, non-directional, or both?

alternative hypothesis

name the hypothesis type:

For patients with limited shoulder mobility, the mean change in external rotation will be different between those who receive mobilization and those who do not

probability

defined as the likelihood that any one event will occur, given all possible outcomes

0-1

What is the range of probability values?

The event will absolutely never occur

What does a probability of 0 mean?

The event is certain to occur

What does a probability of 1 mean?

population characteristics

probability is important because it provides a guideline for how well sample data estimate _____

Whether the observed effects are likely to have occurred by chance

What does probability help determine about observed effects in research?