Understanding Standards Event Higher Statistics Award
Hypothesis Testing David Young Department of Mathematics & Statistics University of Strathclyde NHS, Greater Glasgow and Clyde
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
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
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 – http://www.adweek.com/digital/selfie-generation/ Twitter’s most retweeted post of all time … Twitter’s most retweeted post of all time …
Use this slide for large images, graphics or tables.
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
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
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
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 https://www.drugs.com/omeprazole.html
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
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
Pain assessment score
Hypothesis Testing
Hypothesis Testing
Hypothesis Testing
Hypothesis Testing
Hypothesis Testing
Hypothesis Testing
Hypothesis Testing
Hypothesis Testing
Hypothesis Testing
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Hypothesis Testing
Interpretation If the difference was not due to chance why did it happen?
Interpretation If the difference was not due to chance why did it happen? When is this claim valid?
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?
Additional Points errors in hypothesis testing – p<0.01! null and alternative hypotheses cranberry juice – randomisation http://www.ncbi.nlm.nih.gov/pubmed/22961092
Additional Points double blind studies http://www.theguardian.com/society/2005/jan/17/health.medicineandhealth placebo trials comparison of baseline characteristics intention-to-treat and per-protocol – weight loss example tests for correlation, regression and normality testing
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?
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