Probability and Significance

Question 1

explain levels of significance and probability?

Answer 1

• the usual level of significance= p≤0.05
• the term ‘significance’ can used when describing a correlation
• but could also be 0.01 chance that the study is due to chance

Question 2

whats the difference between descriptive statistics and inferential tests?

Answer 2

• descriptive stats= measures of central tendency and measures of dispersion
• inferential tests= tell us whether any observed differences can be identified and if the the descriptive stats are significant or due to chance (unlike descriptive stats)

Question 3

explain the critical value?

Answer 3

• once the statistical test has been calculated the result number is the OBSERVED VALUE
• this number is then compared to the critical value

Question 4

explain using tables of critical value?

Answer 4

• one tailed test= directional hypothesis
• two-tailed test= non-directional hypothesis
• number of pp’s= n sometimes degrees of freedom are calculated (df)
• level of significance= 0.05

Question 5

explain a type 1 error?

Answer 5

• lenient
• these errors are more frequently made the more lenient a probability level is eg. 0.10
• we would reject the null hypothesis claiming there is an effect but there actually wasn’t one

Question 6

explain a type 2 error?

Answer 6

• strict
• made when the value is closer to 0 eg. 0.01
• this is when we accept the null hypothesis and say there is no effect, but there was we couldn’t see it because the probability was so stringent