Research Methods L13-16 Flashcards
What is quantitative data?
Numerical data that can be measured objectively. Includes: - DV in an experiment. - closed questions (questionnaire) - structured interviews. Etc.
What is qualitative data?
Data involving words which is only quantifiable if put into categories and the frequency is counted.
Includes:
-open questions.
- transcript from unstructured interview.
- researchers describing what they see in an observation.
Advantages and disadvantages of quantitative and qualitative data?
Quantitative: \+ easy to analyse. - provides limited information. Qualitative: \+provides detailed info. - relies on interpretation by the researcher which could be subjective/biased/inaccurate. - difficult to categorise.
What is primary data? +/-?
Data that is collected directly by the researcher fir the purpose of the investigation.
+ up to date.
+ reliable.
- time consuming.
What is secondary data? +/-?
Data that was collected for a purpose other than the current use.
+saves time and money.
- lack of reliability.
- data may have changed over time
What is a meta-analysis? +/-?
The process of combining results from a number of studies on a particular topic (secondary data) go provide an overall view.
+ results can be generalised across large populations.
+ increases validity
- prone to publication bias. Researcher may leave negative results out.
What are the 4 ways of representing quantitative data?
- Tables (with explanation paragraph below).
- Scattergraph.
- Bar chart.
- Distributions.
Scatter graph?
A graphical display that shows the correlation or relationship between two co-variables.
- indicates the strength and direction of the correlation between the co-variables.
- dots are plotted to represent each pair of scores.
Bar chart?
Used to show frequency for discrete (separate) variables.
- height of each bar represents frequency.
- space left between each bar to indicate lack of continuity.
Distributions?
- Normal distribution = symmetrical curve. The mean, mode and median occupy the same midpoint of curve.
- positive skew= data mostly concentrated to left of the graph. Mode remains at highest point of peak, then median and mean dragged across to right.
- negative skew= opposite of +.
What are the measures of central tendency?
Mean, median, mode
What are the measures of dispersion?
Range, standard deviation.
Mean? +/-?
Calculated by adding all the scores and dividing by the number of scores.
+ representative of all data.
+ most sensitive measure of central tendency.
- can be distorted by a single extreme value which will give inaccurate results.
Median?+/-?
Calculated by arranging scores in order and choosing the numerical midpoint.
+ unaffected by extreme values.
- less sensitive than mean.
- not representative of all findings.
Mode? +/-?
Most frequent value in a data set.
+ unaffected by extreme values.
- tells nothing about other values in the data set.
Range? +/-?
Calculated by taking lowest score from the highest.
+ quick and easy to calculate.
- easily distorted by extreme values.
Standard deviation? +/-?
Is the average amount that each score differs from the mean.
+ takes all values into account.
- more difficult to calculate than range.
Percentages?
(Number in pps in condition / total pps) x 100
What is the sign test and when is it used?
The sign test is a statistical test of difference that allows a researcher to determine the significance of their investigation.
It is used in studies that have repeated measures design (one group of pps) and when data is numerical.
How is a sign test carried out?
- State the hypothesis:
- directional hypothesis = one tailed test.
- non directional hypothesis = two tailed test. - Record data and work out sign: subtract before value from after value. Write a sign (+ or -)
- Find calculated (S) value:
- calculate separately how many + and - signs. Smaller value = S. - Find critical value:
- N = total number of scores. Use table of critical values to find the critical value.
