2012 Unit 3 Question Thread.

[Camo]

Here is a question thread for all the psych go-getters next year and any questions they may have.

[vagrantshades]

Which type of sleep is easiest to wake up from? I know NREM Stages 1 & 2 are easy to wake up from, as well as REM, but is there a type of sleep that is EASIEST to take up from?

[Slumdawg]

Which type of sleep is easiest to wake up from? I know NREM Stages 1 & 2 are easy to wake up from, as well as REM, but is there a type of sleep that is EASIEST to take up from?

REM is actually hard to wake up from, it's considered a deep form of sleep. If they asked which one is easiest to wake up from I'd put NREM stage 1

[vagrantshades]

Which type of sleep is easiest to wake up from? I know NREM Stages 1 & 2 are easy to wake up from, as well as REM, but is there a type of sleep that is EASIEST to take up from?

REM is actually hard to wake up from, it's considered a deep form of sleep. If they asked which one is easiest to wake up from I'd put NREM stage 1

Oh thanks mate! Oxford text states that it's easy to wake from. Shows that I need to definitely get my hands on Grivas.

[Slumdawg]

No worries, but yeah Oxford makes a few little errors like that. But that's quite bizzare that they got a detail like that wrong, they must have gotten confused or something because straight after a period REM sleep it's often easier to wake someone. But during REM it's difficult, which makes sense because the person is usually dreaming so it's difficult to snap them out of it.

[vagrantshades]

Okay, another question. Oxford text states that 'Slow-Wave' sleep refers to both Stage 3 and 4 NREM sleep, but my dictionary states that Stage 4. Which one is it?

[totaled]

Okay, another question. Oxford text states that 'Slow-Wave' sleep refers to both Stage 3 and 4 NREM sleep, but my dictionary states that Stage 4. Which one is it?

this is again a bit of grey area, i personally would go with stage 3 and 4 NREM sleep,
in the grivas book it states: Delta waves make up about 20-50% of brain waves during stage 3, and the presence of detla waves marks the beginning of 'slow wave sleep (SWS)'. it also states stage 3 sleep is the start of the deepest period of sleep, so personally i would go for stage 3 and 4 NREM, but i wouldn't be too concerned with such subtleties

[monica3]

i've got two questions! it's from one of my learning activities haha!

1) Explain with reference to an example whether a study can have internal validity but not external validity.

2) Explain with reference to an example, why reliability is possible without validity but validity requires reliability

Much appreciated! haha!

[vagrantshades]

Okay, for question 2) (I'm not completely sure if I'm right but I'm just going to harvest a guess...)

So reliability judges the consistency of the results of an experiment. This means that if an experiment is reliable, it will always obtain the same results when performed with other experimenters, other participants, etc.
However, validity judges how accurately the experiment is testing the cause-effect relationship. Thus, if an experiment shows validity, then it is accurately testing for a relationship between the independent and the dependent variables.

So, reliability can be possible without validity because an experiment can consistently produce the same results when performed with other experimenters and other participants, but it doesn't have to accurately test the cause-effect relationship.

But for an experiment to be valid, and thus accurately testing the relationship, it wouldn't make sense if it didn't consistently test this relationship. For as the experiment is ACCURATE, why would it obtain different results with another experimenter if performed accurately? Thus validity requires reliability.

Sorry if that doesn't make sense - I know I need to use an example but I'm in my pjs and need to go have breakfast. I think that's the answer anyway (but not 100% sure). I would answer 1) as well but like I said, need my breakie.

[monica3]

ohhh! i get it nows!
thanks heaps

[vagrantshades]

Just another question I came across. What exactly is the relationship between the thalamus and the RAS? I know that the RAS controls levels of attention and consciousness, and that the thalamus enables an organism to pay attention to sensory stimuli, but I find it difficult to exactly explain this relationship.

Would it be to do with the RAS regulating the amount of attention required when the thalamus is perceiving sensory information in the environment, and increases the level of attention when the thalamus focuses on a particular stimulus to the exclusion of others?

[orangejuice]

hey guys, was wondering what is the difference between stratified sampling and stratified-random sampling?

[totaled]

not a whole lot, this was one of the ambiguous thing sin psychology, i only ever saw one question (i think on a tft paper) on it out of the 30ish exams i did, but pretty much one is slightly more lenient in that while it is stratified, you might give leeway just to make it a bit more convenient. not a big difference huh?

[Slumdawg]

hey guys, was wondering what is the difference between stratified sampling and stratified-random sampling?

Basically, in stratified sampling once you've split up your population into various segments (i.e. strata) based on a particular characteristic then you need to actually pick participants from each segment. This procedure might be random (giving everyone an equal opportunity to be selected), it might be biased (purposefully picking people who are more likely to support your hypothesis), it might be convenient (pick whoever is available)... Now with stratified-random sampling it involves splitting up the population and then randomly picking participants from each segment.. Whilst with stratified sampling it involves splitting up the population and then picking participants but the selection technique used may be any of the three outlined above (random, biased or convenient)...

So basically stratified random sampling is just giving you more information about the sampling procedure and is more specific than the broader term "stratified sampling" which can incorporate a few different features.

[Scooby]

Hey, can anyone explain descriptive and inferential statistics?