inferential statistics etc

What is a null hypothesis?

a hypothesis that suggests there will be shows no significant difference/correlation any difference is due to chance

Describe when you reject or accept the null hypothesis

Any test with an R (e.g chi squaRed) If observed value is gReateR than or equal to the critical value then you reject the null hypothesis (if it’s less than, you have to accept).

For the other tests without an R is the observed value is less than or equal to the critical value then you reject if it’s more then CV you accept.

What is a hypothesis?

A predictive statement about what the researcher expects to find.

What is test of difference ?

No significant difference any difference is due to change

What is a test of correlation?

Assess the relationship between two variables.

What is a non directional (two-tailed ) hypothesis for test of difference and correlation?

• Test of difference - there is a significant difference but doesnt tell which is better than the other

• Test of correlation - there is a significant correlation but doesnt state how

What is a directional (one-tailed ) hypothesis for test of difference and correlation?

• Test of difference - there is a significant difference and tells you which is better than the other

• Test of correlation - there is a significant correlation and states how

What are the three types of experimental designs?

• Repeated measures

• Independant groups

• Matched pairs

What are repeated measures and give an example?

• same participants do all the condition of the research

  • e.g the same class do a test if they’re better doing a test in morning or afternoon

Give 2 strengths and weakness of repeated measures design

• + Requires less ptp therefore saves time and money, control of ptp variables e.g age, height

• -order of conditions may affect performance (they may do better 2nd time round ), subect to demand characteristics bc they may guess aim 2nd time,

What are independent groups and give an example

• Different particiants in each of the condition of research

  • e.g. chosing random students to complete the test in the morning and a different set of students to complete the test in the afternoon.

Give 2 strengths and 2 weaknesses of independent group design

• + ptp only experienced 1 condition so less likely to guess aim, avoid order of effect, demand characteristics

• - more ptp are needed, individual differences of ptp may affect results

What are matched pairs and give an example

• Different participants in each of the condition of the research but specific chatacteristics are paired to control them

  • e.g. Rain et al controlled charactersictics cush as age, sex and schizophrenic or not.

Give 2 strengths and 2 weakness of matched pairs design

• + ptp only experienced 1 condition so less likely to guess aim so avoids demand characteristics and order of effect, also avoid individual differences bc ptp are matched

• - requires many ptp, difficult to find almost identical ptp

When do you reject the null hypothesis id the tst contains an R ( e.g. chi-squaRed

What are the levels of measurement?

• Nominal

• Ordinal

• Interval

• Ratio

What are the 6 variables?

• Independent Variable

• Dependant Variable

• Co-Variables

• Operationalisation

• Extraneous Variables

• Confounding Variables

What are cofounding variables and extraneous variables?

• Extraneous Variables – Unwanted variables in research that may affect the outcomes, they are consistent, affect all ptp equally

• Confounding Variables – Unwanted variables in research that may affect the outcomes they are inconsistent and affect only some of the ptp

What are co variables and operationalisation variables?

• Co-Variables – The two variables being measured in a correlational study.

• Operationalisation – Defining variables in a way it can be easily measure/ manipulated.

What are independent and dependent variables?

• Independent Variable – What is being manipulated by the researcher;

• Dependant Variable – What is being measured by the researcher

What are 2 strengths and 2 weaknesses of using the mean?

• + Necessary standard deviation, It can always be found when using ordinal or above level data.

• - Influenced by anomalous results, may produce a It may produce value not in the original data set.

What are 2 strengths and a weaknesse of using the median?

• + not influenced by anomalous results, can always be found when using ordinal or above level data.

• - It may produce a value that was not in the original data set.

Give 2 strengths and a weaknesse of using the mode?

• + easy to calculate, It can be used for nominal data

• - There may be more than one result, or no results at all if the data set is quite varied.

Give 2 strengths and a weakness of range

• + easy to calculate, indicates reliability of data,

• - influenced by anomalous results

Give a strength and weakness of standard deviation

• + reflects every score in data set,

• - time consuming

Why would a researcher use a matched pairs experimental design?

Ptp only take part once so less likely to show order effects.

What is meant by ratio data?

The level of measurement that has equal intervals between mean scores and has an absolute or zero point