sign test and probability

Question 1

what is the standard P value (probability value) used in psychology

Answer 1

0.05

Question 2

if the P value is less than or equal to 0.05, what does this means in terms of significance of data

Answer 2

there is a less than or equal to 0.05 chance that the data is caused by chance.
therefore you are 95% sure that manipulating the IV is causing the results

Question 3

what kind of studies do you need a P value of 0.01

Answer 3

medical trials

Question 4

what 3 factors do you need to look out for to ensure you can carry out the sign test

Answer 4

• difference in our data sets
• repeated measure design
• nominal data/discrete data/categoric data

Question 5

how do you know if your data is significant

Answer 5

when the calculated value is less than or equal to the critical value

Question 6

when the data has been put through the sign test

what is the name of the number that you have left

Answer 6

the calculated value

Question 7

once you have your calculate value, what do you do with it

Answer 7

compare calculate value with critical value to establish whether the data is significant or not

Question 8

if you conduct a study with 20 participants

10 +
6 -
4 =

1. what do you take as your calculated value (S value)
2. how many participants do you have (N number)

Answer 8

1. 6
   (least frequently occurring sign not including =)
2. 16
   (if a participant doesn’t score better or worse then you remove them from your data set)

Question 9

What are the three pieces of information you need to know about the study to use the critical value table

Answer 9

• Level of significance desired (if doesn’t specify assume 0.05)
• The number of participants used (N)
• Whether the hypothesis is one or two tailed