revsion pp: stats

Question 1

Common Quan Stats
P-Value

Answer 1

Measures probability that observed difference is chance. The lower the score, the less likely due to chance, and so the more likely it is significant (significant = p-value <0.05)

Question 2

Common Quan Stats
T-Test

Answer 2

• inferential statistic
• the difference between means of 2 sets of data.
• The bigger the score, the more likely the test is repeatable.

Question 3

Common Quan Stats
Pearson’s correlation

Answer 3

• numerical x 2
• age and BP
  Linear relationship - directly impact each other

An interval statistic – measures a linear relationship between 2 variables, where a change in one variable causes a proportional change in the other (e.g. age and BP)

Question 4

Common Quan Stats
Spearman’s correlation

Answer 4

• categorical (ordinal) + numerical variable

An ordinal or monotonic statistic – the variables change together, but not necessarily at the same rate

Question 5

Common Quan Stats
ANOVA

Answer 5

categorical (ordinal or nominal) + numerical variable

need at least 3 categories; social media use (low, medium, high)
hours of sleep (6,7,8)

Question 6

Common Quan Stats
Chi2

Answer 6

Categorical (nominal) x 2
- eg. eye colour and hair colour linked

• A categorical statistic - looking for independence of data (one variable not related to the other)

Question 7

Common Quan Stats
Cohen’s Kappa coefficient

Answer 7

Measures inter-rater reliability, e.g. performing GCS – assessing if agreement is by chance

1 = complete agreement
-1 = complete unagreement
0 = agreed by chance

Question 8

Common Quan Stats
Confidence Interval

Answer 8

The confidence you have that the result will lie between a predetermined range of values

Sample and sample Error
There will always be sampling error because the sample will not 100% represent the whole population
Variation & sample size impact confidence interval
Larger variation and small sample size = large confidence interval

Question 9

Common Quan Stats
Intention to Treat

Answer 9

Including results from participants who do not complete the trial (e.g. died or withdrew) – maintain the original randomised groups of participants

Question 10

Common Quan Stats
Is a higher confidence interval better?

Answer 10

A large confidence interval suggests that the sample does not provide a precise representation of the population mean, whereas a narrow confidence interval demonstrates a greater degree of precision.

Question 11

Common Quan Stats
Descriptive statistics -

Answer 11

mean, median, mode, standard deviation – terms used to describe numbers and patterns

Question 12

Common Quan Stats
Inferential statistics

Answer 12

used to determine the statistical significance of any observed differences between groups

Question 13

Common stats
What p-value makes something statistically significant

Answer 13

= or less than 0.05

0.05 means 5% by chance
reject null hypothesis (no effect)
accept alternative hypothesis (the independent variable caused an effect)