2. Understanding Standards Event Higher Statistics Award

3. Hypothesis Testing David Young Department of Mathematics & Statistics
University of Strathclyde
NHS, Greater Glasgow and Clyde

4. Overview Welcome to the University of Strathclyde
introduction to SQA level 6 Statistics Award
(SQA Home > National Qualifications > Subjects > Statistics Award (SCQF level 6)
how statistics can answer important questions
practical sessions using Minitab and/or R

5. What is statistics …?
statistics is the science of collecting, analysing, presenting and interpreting data
it enables the objective evaluation of research questions of interest
it provides the means to weigh up how much evidence the collected data provide for and against the research hypothesis of interest
statistics are available on almost every aspect of daily life

6. 2014 – the year of the selfie …
millions are shared each and every day across all the major social media platforms
according to data from Samsung, selfies make up almost one-third of all photos taken by people aged 18-24
Facebook, WhatsApp, Twitter, Instagram and Snapchat bearing the brunt of that load
Link –
Twitter’s most retweeted post of all time …
Twitter’s most retweeted post of all time …

7. Use this slide for large images, graphics or tables.

8. Addressing important questions
Can you get diabetes from eating too much sugar?
What are the side effects of too much vitamin D?
Is smartphone addiction a real phenomenon?
Does eating turkey at Christmas make you tired?
Does vitamin C make you look younger?
Is paracetamol better than codeine for treatment of pain?
‘Two heads are better than one’.
Statistics can be used to answer such questions

9. Not always a clear answer …
turkey makes you tired because it’s loaded with tryptophan
tryptophan is a pre-cursor to serotonin which is a mood modulator, inducing relaxation and supporting sleep
tryptophan alone does not make you tired
combining tryptophan with carbohydrates does
it is not the turkey that’s causing Christmas sleepiness, it’s the turkey plus the cranberries, rolls, and pie
turkey actually has less tryptophan than chicken

10. Drug development
pharmaceutical companies have to gather data on drug performance
a drug cannot be used commercially until the company have produced evidence of efficacy and safety
statistical tests (known as hypothesis test) can be used to gather this evidence

11. Omeprazole
Omeprazole (Prilosec, Zegerid) belongs to a group of drugs called proton pump inhibitors
it decreases the amount of acid produced in the stomach
Omeprazole is used to treat symptoms of gastroesophageal reflux disease (GERD) and other conditions caused by excess stomach acid
common side effects may include: stomach pain, gas, nausea, vomiting, diarrhoea or headache

12. Statistics and Probability
statistical analysis considers the probability of an event being due to chance
can never be 100% certain for example that one treatment is better than another
can say mathematically how sure we are that a result is true

13. Probability hypothesis: all dogs can bark how would you prove this?
data has to be gathered to give evidence for or against the hypothesis
a hypothesis test has to be performed

14. Pain assessment score

15. Hypothesis Testing

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24. Hypothesis Testing

25. Hypothesis Testing

26. Hypothesis Testing

27. Interpretation
If the difference was not due to chance why did it happen?

28. Interpretation
If the difference was not due to chance why did it happen?
When is this claim valid?

29. Interpretation
If the difference was not due to chance why did it happen?
When is this claim valid?
What are the consequences of getting it wrong?

30. Additional Points errors in hypothesis testing – p<0.01!
null and alternative hypotheses
cranberry juice – randomisation

31. Additional Points double blind studies
placebo trials
comparison of baseline characteristics
intention-to-treat and per-protocol – weight loss example
tests for correlation, regression and normality testing

32. Two heads are better than one …?
study design?
what were the rules for doing the quiz?
randomisation?
double blind?
how many participated – why is this important?
who marked?
are you satisfied that the groups were comparable?