Correlations and descriptive stats.

Question 1

What is a scattergram?

Answer 1

A type of graph that represents the strength and direction of a relationship between co-variables in a correlational analysis.

Question 2

What is a correlation?

Answer 2

Demonstrates a relationship between two variables on a scattergram.

Question 3

What is the difference between an experiment and a correlation?

Answer 3

-Experiments manipulate the IV to measure the effect on the DV, in order to establish a cause for the difference in DV.
-Correlations just state a relationship but does not say one causes another.

Question 4

How to tell the strength of a correlation?

Answer 4

How close the points are to the line of best fit.

Question 5

What are correlation coefficients?

Answer 5

Measures the strength and direction of a linear relationship between two variables on a scatter plot.
-Closer to -1 strongest negative.
-Closer to 1 strongest positive.

Question 6

Advantages of correlations?

Answer 6

-quick and economical to carry out
no need for controlled environment/ manipulation of Vs
can be used when its unethical to manipulate Vs to see if one V affects the other
-if a relationship is found, then it can justify other research

Question 7

Disadvantages of correlations?

Answer 7

-Can not tell cause and effect!
-May have the third variable problem.
-Can be misused and misinterpreted by the media.

Question 8

What is qualitative data?

Answer 8

Expressed in words (written descriptions, thoughts feelings from interviews or open questions).
-Greater external validity.
-Difficult to analyse.

Question 9

What is quantitative data?

Answer 9

numerical data
-From closed questionnaires, experiments.
-Simple to analyse.
-lacks detail and external validity.

Question 10

What is primary data?

Answer 10

Data collected by the researcher FOR THE SPECIFIC PURPOSE OF THE RESEARCHER.
-Authentic and up to date.
-More time and effort.

Question 11

What is a meta analysis?

Answer 11

-The results from a number of studies investigating the same hypothesis are identified and reviewed, to produce a joint conclusion.

Question 11

What is secondary data?

Answer 11

information that already exists somewhere, having been collected for another purpose.
-easy to access and inexpensive.
-may not fit the investigation.

Question 12

Advantages of meta analysis?

Answer 12

It creates a larger more valid sample because it can be generalised more.

Question 13

Limitations of meta-analysis?

Answer 13

• inclusion of poorly conducted studies in equation
• cost of conducting the study
• criteria being used for including primary sources are difficult to agree upon
• incomplete data sets
• publication bias as researcher may not use studies that contradict the hypothesis.

Question 14

What is a measure of central tendency?

Answer 14

finding the most typical value in the data.

Question 15

Mean:

Answer 15

Obtained by adding the scores and then dividing by the number of scores.
-Sensitive and extreme values will distort it.

Question 16

Median:

Answer 16

Order the data and is the middle number.
-Not affected by extreme values but less sensitive than the mean.M

Question 17

Mode:

Answer 17

The most common value.
-Easy to calculate but most of the time does not represent the data well.
-Good more categoric data.

Question 18

What are measures of dispersion?

Answer 18

Measurements of the spread of scores within a set of data and include the range, standard deviation and variance.

Question 19

Range:

Answer 19

the difference between the highest and lowest scores in a distribution.
-1 is often added because results in the data are often rounded, so this accounts for the margin of error.
-Easy to calculate.
-Extreme values distort.

Question 20

Standard deviation:

Answer 20

a computed measure of how much scores vary around the mean score.
-More precise than the range.
-Harder to calculate and can be distorted.

Question 21

What does a larger/smaller standard deviation mean?

Answer 21

Data is more spread out/data is more concentrated around the mean value.

Question 22

What is a normal distribution?

Answer 22

A “normal” distribution is also known as a bell-shaped curve or Gaussian curve. In a Gaussian or normal distribution, the mean , mode and median would all have the same (or similar) value and would look like the figure.

Question 23

What is a positively skewed distribution?

Answer 23

A distribution where the right tail (end) of the distribution is pulled further than the left tail. A distribution where there are more extreme high scores than low scores.
-The mean is more than the mode and median
RIGHT FOOT.

Question 24

What is a negatively skewed distribution?

Answer 24

A distribution where the left tail (end) of the distribution is pulled further than the right tail. A distribution where there are more extreme low scores than high scores.
-Mean is less than the mode and median.
LEFT FOOT.

Question 25

What is a bar chart?

Answer 25

A type of graph in which the frequency of each variable is represented by the height of the bars. Discrete data

Question 26

What is a histogram?

Answer 26

a diagram consisting of rectangles whose area is proportional to the frequency of a variable and whose width is equal to the class interval. Continuous data.