Statistics

Question 1

What is Interval data?

Answer 1

Data measured in fixed units with equal distance between points on the scale
For example: temperature measured in centigrade

Question 2

What is ordinal data?

Answer 2

number score, but the number represents rank position
Example: 1st, 2nd, 3rd, etc. The positions of football teams in a league are examples of ordinal data

Question 3

What is nominal data?

Answer 3

Puts sample into categories, categories them into groups
Example: using “tally marks” to record the number of people in one group or another

Question 4

What is skewed distribution?

Answer 4

Where frequency data is not spread evenly, the data is clustered at one end. Data that is positively skewed has a long tail that extends to the right

Question 5

What does standard deviation find?

Answer 5

Shows the spread of scores from the mean. The greater the standard deviation the greater the spread of scores from the mean.

Question 6

When would you use Mann-Whitney U?

Answer 6

• Test of difference
• Ordinal data
• Independent group design

Question 7

When would you use Willcoxen?

Answer 7

• Test of difference
• Ordinal data
• Matched pairs/repeated measures

Question 8

When would you use Spearman’s rank?

Answer 8

• Test of correlation
• Ordinal data

Question 9

When would you use Chi squared?

Answer 9

• Test of difference
• Nominal data
• Independent group design

Question 10

What is a type 1 error?

Answer 10

False-posative, if an investigator rejects a null hypothesis that is actually true in the population

Question 11

What is a type 2 error?

Answer 11

False-negative, if the investigator fails to reject a null hypothesis that is actually false in the population

Question 12

What do you need to remember when doing standard deviation?

Answer 12

• Deduct the mean from each score in set

Question 13

What do you need to remember when doing Mann-Whitney U?

Answer 13

• Rank separately
• na is the total number of scores you have in Condition A
• nb is the number of scores in Condition B

Question 14

What do you need to remember when doing Wilcoxen?

Answer 14

• Rank together
• Ignore 0
• Add up posative ranks
• Add up negative ranks
• T is the smallest out of the 2
• N is the number of scores

Question 15

What do you need to remember when doing Spearman’s rank?

Answer 15

• Rank separately
• Find difference between condition 1 rank and condition 2 rank
• n = number of participants
• positive = positive correlation
• negative = negative correlation
  (The closer it is to 0 , the weaker the correlation, The closer it is to 1, the stronger the correlation)

Question 16

How do you work out E in Chi squared?

Answer 16

To find E, add up rows/columns
E = (sum of row)x(sum of column)/sum of all