{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Psychology Methods and Designs Overview

# Psychology Methods and Designs Overview - Psychology...

This preview shows pages 1–2. Sign up to view the full content.

Psychology Methods and Designs Overview General Information : I) Types of Variables : a. True IV – the IV levels can be doled out to people randomly b. False IV – the IV levels are predetermined for each individual and outside of the experimenter’s control c. Discrete Variable – each level is a different category i. Level often described by words, not numbers (ex – male/female) ii. No intermediate values iii. Types of Discrete Variables : 1. Ordinal Variable – categories have a logical order (ex – short, medium, tall) 2. Nominal Variable – categories do not have a logical order (ex – sad, mad, happy) d. Continuous Variable – each level is a number i. There are intermediate values ii. Study often has many if not infinite levels (e.g. – height, IQ, reaction time) iii. Types of Continuous Variables : 1. Ratio Variable – if zero really represents no value, the numbers are literal and 2 times a value is really twice the value of the variable (ex – height, age) 2. Interval Variable – otherwise (ex – temperature, IQ) e. Note : i. Good designs don’t turn continuous IV’s into discrete IV’s (loses information) ii. It’s always better to have the DV’s (what you measure) be continuous variables (better for getting significant results) iii. If IV’s are discrete, it’s best to have a balanced number of participants in each level iv. In describing IV and DV, make sure you use operational definitions (very specific and empirically measurable) II) Inferential Statistics : a. Inferential statistics test two competing hypotheses i. H 0 (Null Hypothesis) – nothing is going on (the IV has no causal effect) ii. H 1 (Alternative Hypothesis) – something is going on (the IV has a causal effect) 1. Only one can be true and they describe all the possibilities iii. Process : 1. Begin by accepting H 0 and reject H 0 only if the data contradicts it, which automatically means that you accept H 1 iv. p – probability that H 0 is correct (if p < or = .05, reject H 0 and accept H 1 ) b. Types of Errors : i. Type I Error – wrongly rejecting H 0 (probability of type I error = .05) 1. Make sure that the assumptions of any statistical tests are not violated and one is using “robust” tests, ones that are pretty correct even if some of their assumptions are violated ii. Type II Error – wrongly rejecting H 1 1. Helps to avoid type II errors if there is a lot of participants and the DV is interval/ratio III) Reliability and Validity : a. Reliability – how repeatable and consistent the test is i. Test/Retest Reliability (measures repeatability) – test 1 time 1 = test 1 time 2 1. Only pertains to constructs that are traits, not states a. Traits (stable), states (easily changeable) (e.g. – traits:states::depression:sadness) 2. If the time interval is too short they’ll remember how they answered the test the last time, but if the time interval is too long then the constructs might have changed ii. Internal Consistency (measures consistency with the test) – compares all the items to each other 1. Qualify with Cronbach’s alpha or Cohen’s kappa iii.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern