Biostatistics

Q10. Section 3-2: Systolic Blood Pressure: [6 marks] the systolic blood pressure of 30 randomly selected college students is Use grouped formulas to find approximations for mean, standard deviation, median, P30 and Q3. [1] Xg= [2] Sg5 [1] grouped median [1] P30 [1] Q3 =

Part 1: Can one argue that the relationship between the investigated exposure and outcome is causal? Explain your answer.

Part 2: How likely is the possibility that the results were a mere chance finding? Explain your answer.

Part 3: You were requested to again investigate the association between exposure to noise and hearing loss while also accounting for each worker's age, level of education, past history of a hearing ailment, and presence of comorbidity. What statistical analysis would provide an answer?

Part 4: After you have conducted the analysis in Part 3, the association between exposure to noise and hearing loss weakened and became statistically insignificant. Explain this finding.

In order to target a specific region of genomic DNA with CRISPR, researchers must include a guide RNA containing a 20-basepair (bp) long spacer sequence that matches the DNA sequence at the target site. One of the possible risks of genetic engineering methods is "off-target" editing, which occurs when a guide RNA matches a part of the genome other than the intended target site. (i) How many possible guide RNA sequences are there? (ii) Estimate probability that a single site in the human genome matches a random 20-bp spacer. State all your assumptions. (iii) After infection, HIV converts its RNA genome into DNA and inserts itself into the human genome. Imagine you have designed a 20-bp spacer to target and deactivate part of the HIV DNA sequence. Based on the previous answer, estimate the probability that this sequence will have at least one off-target match somewhere in the human X chromosome, which is 300 000 bp long (counting both strands). Note: when P is very small (close to 0), (1-P)^n is approximately equal to (1-nP). (iv) What would be the probability of an off-target site appearing somewhere in the entire human genome (6 billion pairs counting both strands)?