Semester Two Final Examinations, 2015 STAT1201 Analysis of Scientific Data THE UNIVERSITY OF QUEENSLAND AUSTRALIA This exam paper must not be removed from the venue Venue Seat Number Student Number Family Name First Name Solutions School of Mathematics & Physics EXAMINATION Semester Two Final Examinations, 2015 STAT1201 Analysis of Scientific Data This paper is for Gatton Campus (External), Gatton Campus and St Lucia Campus students. Examination Duration: 120 minutes For Examiner Use Only Reading Time: 10 minutes Exam Conditions: This is a Central Examination Question Mark 1 This is a Closed Book Examination - specified materials permitted 2 During reading time - writing is not permitted at all 3 This examination paper will be released to the Library 4 5 Materials Permitted In The Exam Venue: (No electronic aids are permitted e.g. laptops, phones) Calculators - Casio FX82 series or UQ approved (labelled) One A4 sheet of handwritten notes double sided is permitted Materials To Be Supplied To Students: none 6 Total Instructions To Students: There are 90 marks available on this exam from 6 questions. Each question is worth 15 marks. 1 Write your answers in the spaces provided in Part A (pages 2-16) of this examination paper. The backs of pages in Part A may be used for rough working but these will not be marked. Part B (pages 17-19) gives formulas and statistical tables. Pages in Part B will not be marked. Page 1 of 19
Semester Two Final Examinations, 2015 STAT1201 Analysis of Scientific Data Part A - Questions Question 1 Does heavy mobile phone use affect brain activity? In one study of this question, 47 healthy participants were recruited to undergo scanning to measure brain glucose metabolism (a measure of brain activity) while using a mobile phone. The researchers reported various background characteristics of their sample, such as that the mean mobile use was 1500 minutes/month with a standard deviation of 1850 minutes/month. During the study, each subject had mobile phones placed on both the left and right ears. Brain glucose metabolism was measured twice for each subject, once where both phones were off (the "off" condition) and once where one of the phones was receiving a call (the "on" condition). The phone receiving the call was muted. (a) Based on the background data, give a 95% confidence interval for the mean mobile use (minutes/month) for people in the population. Briefly interpret the interval you obtain. [5 marks] Need the critical value ty, but only t40 =2.021 and tsp=2.009 are available in table. Use the larger one ( to ensure we are at least 95% confident), giving the interval 1500 + 2.021 x 1850 547 = 1500+ 545, so 95% confident that mean mobile use for this population is between 955 and 2045 minutes/month. (b) Let u be the mean difference in brain glucose metabolism between the "off" and "on" conditions for this population. State the null and alternative hypotheses with reference to ?. [2 marks] Ho: M=O vs H1: M=0 Page 2 of 19