Psychology - Research Methods - Math concepts, distributions and statistical testing (sign test)

Question 1

Tables

Answer 1

Tables in the results section of a report are not raw scores, they have been converted to descriptive statistics

Question 2

Descriptive statistics

Answer 2

Measures of central tendency or dispersion

Question 3

What is a Bar chart used for?

Answer 3

These are used for nominal data.

Question 4

Bar charts

Answer 4

The height of each bar represents the frequency of each item. There is a space is between each bar to indicate the lack of continuity. The frequency of each category is plotted on the vertical y-axis.

Question 5

What are Histograms used for?

Answer 5

These are used for ordinal or interval data.

Question 6

Histograms

Answer 6

Similar to a bar chart but the area within the bars must be proportional to the frequencies represented. In practice this means that the y-axis must start at zero. No gaps between the bars.

Question 7

What do line graphs represent?

Answer 7

There are represent ordinal or interval data.

Question 8

Line graphs

Answer 8

Use points connected by lines to show how something changes in value, or, over time. Typically, the independent variable (IV) is plotted on the x-axis and the DV on the y-axis.

Question 9

What do scattergrams/graphs show?

Answer 9

Show relationships between co-variables (correlations).

Question 10

Scattergrams/graphs

Answer 10

Either of the co-variables occupies the x-axis and the other the y-axis. Each point on the graph corresponds to the x and y position of the co-variables. The closer the points on the graph are to a straight line the stronger the correlation.

Question 11

Distributions

Answer 11

With most data sets the frequency of these measurements should reflect a bell shaped curve. This is called a normal distribution curve which is symmetrical

Question 12

skewed distribution

Answer 12

when distributions appear to lean to one side.

Question 13

Positive skew

Answer 13

most of the data is concentrated to the left of the graph, the mode remains at the highest point of the peak, the median comes next but the mean has been dragged across to the right.

Question 14

negative skew

Answer 14

A curve or distribution of scores that has extreme scores below the mean that are atypical of the majority of scores.

Question 15

What are the two types of inferential statistics?

Answer 15

Descriptive and inferential

Question 16

descriptive statistics

Answer 16

measures of central tendency and dispersion

Question 17

inferential statistics

Answer 17

numerical data that allow one to generalize- to infer from sample data the probability of something being true of a population

Question 18

Level of statistical significance

Answer 18

The level at which the decision is made to reject the null hypothesis in favour of the experimental hypothesis. It states how sure we can be that the IV is having an effect on the DV and this is not due to chance.

Question 19

Chance

Answer 19

Something has no real cause it just happens

Question 20

What significance level is used in psychology

Answer 20

p<0.05 (5%), because not too strict or lenient. Minimises chances of type 1 or 2 error

Question 21

What are the steps in doing a sign test?

Answer 21

1) state hypothesis 2) record data and work out sign 3) find calculated value 4) find critical value

Question 22

What are the reasons for using a sign test

Answer 22

Looking for differences in data, Looking at paired or related data, Using nominal data