12. (edited) In a study of intra-observer variability in the assessment of cervical smears, 3325 slides were screened for the presence or absence of abnormal squamous cells. Each slide was screened by a particular observer and then rescreened six months later by the same observer. Two different scientists summarize the results of this study, and they come up with two different tables as shown below: Scientist 1: First Screening 2nd: present 2nd: absent Total Present 1763 489 2252 Absent 403 6'70 1073 Total 2166 1159 3325 Scie'st 2: Abnormal cells lst screen 2nd screen Total Present 2252 2166 4418 Absent 1073 1159 2232 Total 3325 3325 6650 a. Which presentation is better? Why? What is wrong with the presentation you did not prefer? b. Do these data sup port the null hypothesis that here is no association between time of screening and diagnosis? [based on whichever table you chose for P311 [3]}