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Significant Effect or Not?

5. Road accident researchers were interested in the effectiveness of Red Light cameras that can photograph the number plates of cars if they pass through an intersection on a red light. Researchers arranged for speeds to be measured as cars entered intersections. There were two factors under consideration - Presence or Absence of a red light camera, and whether cars were facing a Green or Amber light. The data was collected at four times of day. For this question you will be assigned data from one of these times of day on the basis of the first letter of your last name.
If your last name begins with the letters A-E use data from Time 1
If your last name begins with the letters F-K use data from Time 2
If your last name begins with the letters L-R use data from Time 3
If your last name begins with the letters S-Z use data from Time 4
(a) Did the colour of the light (Green or Amber) influence speed, i.e. was there a main effect of Colour. On a standard answer sheet, state clearly the null and alternative hypotheses (in words) in terms of the effects on light Colour on speed. Attach your calculations, the appropriate statistical decisions, and report your findings as would be done for a journal article
(b) Did presence or absence of a Red Light camera alter speed, i.e. was there a main effect of Camera. On a standard answer sheet, state clearly the null and alternative hypotheses (in words) in terms of the effect of Red light camera on speed. Attach your calculations, the appropriate statistical decisions, and report your findings as would be done for a journal article
(c) Did the effects of light Colour and presence of Camera interact. On a standard answer sheet, state clearly the null and alternative hypotheses (in words) in terms of an interaction of the effects of Camera and light Colour upon speed. Attach your calculations, the appropriate statistical decisions, and report your findings as would be done for a journal article

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Solution Summary

Referring to the scenario, this solution provides a step by step guide to calculating whether there was a significant effect or not.

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