Research and Statistics Exam 3

What is the phrase created before spring break for extra credit?

Instrhob6

In-terstellar

Str-awberry

Hob-bit

6

Population

The total group to whom we want to generalize findings too.

i.e. adults with anxiety, college students, or children with asthma

Sample

A subset of a population being studied

Representative sample

A sample looks like the population.

i.e. students at Lee: 80% females & 20%males, so the sample will represent the same ratio

Probability sampling

Everyone in the population has a chance to be represented in the sample.

What sampling methods are probability sampling?

Cluster, stratified and simple random

Non-Probability sampling

Not everyone in the population has a chance to be represented in the sample.

What sampling methods are non-probability sampling?

Convenience and quota

Quota sampling

Sampling method similar to stratified, make characteristic groups, then look at percentages st which those characteristics exist within the population. Then select from those characteristic groups until you reach a predetermined quota for each group.

Cluster sampling

Population divided into groups then a group is chosen at random; the entire group is then used for sampling

Simple random Sampling

every member of the population has an equal probability of being selected for the sample then the sample is chosen randomly from the list of people in pop.

Stratified sampling

A type of probability sampling in which the population is divided into groups with a common attribute and a random sample is chosen within each group.

Convenience sampling

Sampling in a convenient way. Often biased in some way. Volunteer bias; the type of person willing to approach a booth in the PCSU and take a survey.

Mean

The average

Median

The centermost number

Mode

Most frequently occurring number

Measures of central tendency

Mean, median, and mode

Standard deviation

describes an average distance of every score from the mean

Normal distribution

A bell shaped mound, that is symmetrical.

What is the avg IQ score?

100

What is the standard deviation of the avg IQ score?

15

Central limit theorem

If you get enough samples and data from a population, you will end up with a normal distribution.

As the sample size increases, the distribution becomes more normal and narrower

What is a good sample size?

30

What is a skewed distribution

when a distribution is neither bell shaped or symmetrical

Positive skew

The tail is pointing to the right. the mean is to the left but there are numerous outliers on the right

Negative skew

Tail points to the left. mean is positive but there are numerous outliers in negative.

Alternative hypothesis Ha

The researcher's hyp. prediction about research

"Consistent good sleep will increase GPA"

Null Hypothesis Ho

No difference between groups being compared.

nothing, zero, no difference.

"There will be no difference in students who receive good sleep and those who don't on their GPA".

One tailed hyp

the researcher predicts the specific direction of the expected results in this study.

"Consistent good sleep with increase GPA"

Two-tailed HYP

Researcher does not predict specific outcome.

"consistent sleep will impact GPA"

How many standard deviations away from the mean is an outlier?

3

Steps for testing a hypothesis

Determine the Ho and Ha

Set alpha value (0.05)

Collect and summarize data, run a test statistic

compare results from test statistic and alpha value threshold

make a decision

What is the alpha value threshold always used in psyc?

0.05

What level of confidence is used for psyc?

95%

What is the level of significance

alpha (α), is the probability of incorrectly rejecting the null hypothesis when it is actually true, meaning it's the risk of a Type I error.

What is the equation for the alpha value?

a=1-C

P <= 0.05

Reject the null

statistically significant results

P > 0.05

Fail to reject the null

Statistically insignificant results

What is the P value?

shows how likely it is that your set of observations could have occurred under the null hypothesis

What is the hypothesis testing process?

Propose a hypothesis based on theory

Acknowledge that the hypothesis might be wrong

gather data relevant to the hyp

The data allow us to make a decision

What is hypothesis testing?

Testing for the the null

Skewed population

distribution has a long tail on one end and a short tail on the other

Independent variable IV

The manipulated variable

Dependent variable DV

The measured outcome affected by the IV

Extraneous variable

Something unwanted or unexpected that might affect the dependent variable.

Reliability

the extent to which a test yields consistent result; test-retest, inter-rater, and internal

Validity

The extent to which a measure assesses what it claims to measure

Content, face, predictive, concurrent

What are some types of self report measures

Open ended response, closed response & Likert scale

Can you write your own research question, hypothesis, conceptual and operational definitions, and IV, DV, and EV

Increased exposure to nature-themed audio (sounds of a forest) will lead to a decrease in self-reported stress levels.

Conceptual definition

the abstract or theoretical meaning of a concept being studied

Operational definition

To define in terms you will use to measure it [concept+method]