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2. Research has shown that early onset of hearing loss can be attune to prolonged, intense exposure to music at impacting decibels from headphones and rock concerts. In order to test this relationship, researchers enrolled a group of 25-35 year olds and followed them for 15 years, asking participants to document their music listening habits in a journal that would be regularly checked by the research professionals. The journals would be interpreted and an overall average exposure level over a specified period of time would be quantied into four quartiles based on decibel strength of the music experience the participant endured. Signs or symptoms of early hearing loss would be dichotomized into either expressing a decreased hearing capability or not based on an examination at the end of the study. The following table represents the results of the study. Hearing Loss No Hearing Loss Total Decibel Strength (0-60) 29 85 114 Decibel Strength (61- 100) 41 91 132 Decibel Strength (101-125) 63 123 186 Decibel Strength (>125) 58 79 137 Total 191 378 569 A) What type of study is being conducted here? B) Conduct a formal test of signicance to determine if there is a statistically signicant di'erence in hearing loss between the groups. Write out your null and alternative hypotheses and interpret your results at the alpha level of 0.05. C) Calculate the appropriate risk measure comparing each of the highest three decibel level groups to the rst as a reference (non-exposed) group. D) Based on your results in B and C, describe the relationship between hearing loss and average overall decibel strength over the follow-up time. Is there a dose-response relationship? Ans: A) Cohort study B) Chi-Square Ho: no association between decibel strength and hearing loss in the source population Ha: association exists between the variables. Xi-Square stat=8.48 3 df Byglge 0.03? Reject the Ho that there is no association between decibel of music strength and hearing loss. C) Ri(2tol)=1.222, ji to 1)= 2.007, 31111114 to 1)=1.654 D) There is a slight dose-response relationship. Observed risk for hearing loss is highest when the decibel strength is between 101 and 125