Semester One Mid-semester Examinations, 2017 STAT1201 Analysis of Scientific Data Question 1 Studies have shown that heating the scrotum by just 1 degree Celsius can temporarily reduce sperm count and sperm quality. A recent study1 examined the effect of using a laptop computer on the lap on the changes in scrotal temperatures. A total of 150 male participants were randomly assigned to one of the three sitting conditions (legs together, legs apart, and legs together with a laptop cooling pad). Each participant was asked to use the same laptop to watch the same video for 60 minutes, after which the changes in scrotal temperatures were recorded. Boxplots of the data are given below. Scrotal temperature increase with laptop computer on lap under three sitting conditions 5 0 000 0 4 - ~ - Scrotal temperature increase (degrees C) N- -- 0 LegsTogether LegsApart LapPad a) Compare and contrast the three distributions in terms of centre, spread and shape. [3 marks] Legs Together has the highest centre. Legs Together and Lapped have similar spread, with Legs Apart having much lower spread. Legs Together and Legs Apart seem roughly symmetric while LapPad is skewed to the right 1 Sheynkin, Y., et al, (2011) "Protection from scrotal hypothermia in laptop computer uses", Fertility and Sterility, 92, 647-651. Page 2 of 13 .
STAT1201 Analysis of Scientific Data Semester One Mid-semester Examinations, 2017 b) Match the following histograms to their corresponding sitting conditions. [2 marks] (i) (ii) (iii) 25 25 12 20 15 - Percent of Total 10 - 20 15 Percent of Total 10 10 8 Percent of Total 4 5 - 5 - 2 0 0 0 0 1 2 3 4 5 Scrotal temperature increase (degress C) 0 1 2 3 4 5 Scrotal temperature increase (degress C) 1.0 1.5 2.0 2.5 Scrotal temperature increase (degress C) Histogram (i) corresponds to sitting condition Cap Pad (skewed) Histogram (ii) corresponds to sitting condition Legs Together (symmetric) Histogram (iii) corresponds to sitting condition Leas Apart (narrow range) c) Studies have also suggested that heating the scrotum by over 2 degrees Celsius can cause long-term, irreversible damage to sperm count and sperm quality. In light of this, which of the three sitting conditions would you recommend to a male friend who is going to be using a laptop computer on his lap to watch a movie tonight? [1 mark] Lap Pad Briefly justify your recommendation. [2 marks] For (1), only = 28% were over 2?, compared to = 36% for (iii) and 70% for (i) Page 3 of 13
Semester One Mid-semester Examinations, 2017 STAT1201 Analysis of Scientific Data Question 2 A recent study examined the link between miscarriage and the use of painkillers during pregnancy. Scientists interviewed 1009 women soon after they got positive results from pregnancy tests about their use of painkillers in the early weeks of pregnancy. The researchers then recorded which of the pregnancies were successfully carried to full term. The results are given in the table below: Aspirin Ibuprofen