Presentation is loading. Please wait.

Presentation is loading. Please wait.

Produced by MEI on behalf of OCR © OCR 2013 Introduction to Quantitative Methods Statistics Bringing it all together.

Similar presentations


Presentation on theme: "Produced by MEI on behalf of OCR © OCR 2013 Introduction to Quantitative Methods Statistics Bringing it all together."— Presentation transcript:

1 Produced by MEI on behalf of OCR © OCR 2013 Introduction to Quantitative Methods Statistics Bringing it all together

2 Produced by MEI on behalf of OCR © OCR 2013 Statistical cycle

3 Produced by MEI on behalf of OCR © OCR 2013 Coming to a conclusion So you have asked an interesting question collected some relevant data done some calculations and presented the data in a helpful way How do you come to a conclusion?

4 Produced by MEI on behalf of OCR © OCR 2013 “The mean time to do the coordination test before drinking coffee was 36.8 s. The mean time to do the coordination test after drinking coffee was 36.9 s. So I conclude that drinking coffee makes peoples’ coordination worse.” Any comments about this conclusion? Significance Imagine an experiment to test whether drinking coffee changes the time it takes to perform a test of coordination.

5 Produced by MEI on behalf of OCR © OCR 2013 Significance “The mean time without the catalyst was 28.1 s. The mean time with the catalyst was 27.3 s. So I conclude that the catalyst speeds up the reaction.”

6 Produced by MEI on behalf of OCR © OCR 2013 Catalyst data Scenario A Times without catalyst 28.0 28.1 28.1 28.2 Mean = 28.1 s Time with catalyst 27.1 27.2 27.4 27.5 Mean = 27.3 s Scenario B Times without catalyst 26.9 27.4 28.5 29.6 Mean = 28.1 s Time with catalyst 26.9 26.9 27.0 28.4 Mean = 27.3 s

7 Produced by MEI on behalf of OCR © OCR 2013 Being certain In maths you can be sure that some things are always true; you can prove them. ‘If you add two odd numbers you always get an even number.’ In statistics you cannot be so certain. You collect evidence from a sample, and you come to a conclusion about the population. ‘There is good evidence to suggest that the catalyst speeds up the reaction.’ ‘There is not enough evidence to suggest that coffee affects coordination.’

8 Produced by MEI on behalf of OCR © OCR 2013 Experimenter bias There is not enough evidence to suggest association between playing violent video games and real world behaviour There is evidence to suggest association between playing violent video games and real world behaviour

9 Produced by MEI on behalf of OCR © OCR 2013 Air pollution conclusion Is air pollution worse in the Eastern region now, compared with 40 years ago?

10 Produced by MEI on behalf of OCR © OCR 2013 Air pollution conclusion

11 Produced by MEI on behalf of OCR © OCR 2013 Air pollution conclusion

12 Produced by MEI on behalf of OCR © OCR 2013 19752010 range84 inter-quartile range11 semi inter-quartile range0.5 19752010 mean3.42863.2195 median33 mode33 19752010 minimum12 lower quartile33 median33 upper quartile44 maximum96 Measures of central tendency Five number summary Air pollution conclusion Measures of spread

13 Produced by MEI on behalf of OCR © OCR 2013 Evaluation

14 Produced by MEI on behalf of OCR © OCR 2013 Acknowledgements Picture of chemical experiment by Agriculture And Stock Department, Information Branch, Photography SectionAgriculture And Stock Department, Information Branch, Photography Section http://commons.wikimedia.org/wiki/File:Queensland_State_Archives_1857_Agricultural_Chemical_Laboratory_Departm ent_of_Agriculture_and_Stock_Brisbane_c1955.png Public domain


Download ppt "Produced by MEI on behalf of OCR © OCR 2013 Introduction to Quantitative Methods Statistics Bringing it all together."

Similar presentations


Ads by Google