1 | P a g e | © copyright 2024/2025 | Grade A+
SJSU Final Exam Bio 155/55
Questions and Correct Verified
Answers Latest Version
2 x 2 Table
✓ 2 variables:
✓ -1 variable: treatment/ Intervention/ Factor
✓ -2nd variable: outcome/ Event
✓ There are frequencies analyzed in a 2 x 2 contingency table
Risk
✓ -Probability an event will occur
✓ -Risk in one group: # of individuals with the outcome/ total # of
individuals in that group
Relative Risk:
Master01 | September, 2024/2025 | Latest update
, 1 | P a g e | © copyright 2024/2025 | Grade A+
✓ -Aka risk ratio
✓ -Ratio of risks for 2 groups
✓ -RR = (risk of intervention group/risk for reference group)
✓ -RR = 1 means risk is the same
✓ -RR > 1 patients with paclovid are more likely to be hospitalized than
placebo
✓ -RR<1 patients with paxlovid less likely to get hospitalized than placebo
Relative Risk reduction (RRR):
✓ -proportionate reduction in risk for the intervention group relative to
refrence group
✓ -RRR = ( risk for reference group - risk for intervention -group / risk for
refrence group ) x 100
✓ -Interpretation example: RRR= 88.8837%, paxlovid groups risk of HOD is
reduced by 88.9% relative to the placebo group
✓ -Reference = placebo group
✓ -Intervention = paxlovid
How was alpha =0.05 determined?
Master01 | September, 2024/2025 | Latest update
, 1 | P a g e | © copyright 2024/2025 | Grade A+
✓ -R.A. Fisher wrote a book in 1925 he put statistical tables used to
determine statistical significance
✓ -Needed a separate table for each df which was too many
✓ -He chose alpha= 0.05
✓ -Is arbitrary, feels reasonable, it works, socially accepted
✓ -intended as a first look
✓ -If alpha = 0.02 that means there is a 2% chance of making a type one
error. Decreasing type one error we increase the chance of a type two
error ( missing significant findings )
Using Alpha and Null Hypothesis significance Testing( NHST)
✓ -Caused by the p-value there is dichotomy( 2 outcomes ) which are
significant p< alpha and non significant p> alpha
✓ -Significant also called positive findings ( most published)
✓ -non significant also called negative findings (put in the file drawer)
Importance of negative findings
Master01 | September, 2024/2025 | Latest update
SJSU Final Exam Bio 155/55
Questions and Correct Verified
Answers Latest Version
2 x 2 Table
✓ 2 variables:
✓ -1 variable: treatment/ Intervention/ Factor
✓ -2nd variable: outcome/ Event
✓ There are frequencies analyzed in a 2 x 2 contingency table
Risk
✓ -Probability an event will occur
✓ -Risk in one group: # of individuals with the outcome/ total # of
individuals in that group
Relative Risk:
Master01 | September, 2024/2025 | Latest update
, 1 | P a g e | © copyright 2024/2025 | Grade A+
✓ -Aka risk ratio
✓ -Ratio of risks for 2 groups
✓ -RR = (risk of intervention group/risk for reference group)
✓ -RR = 1 means risk is the same
✓ -RR > 1 patients with paclovid are more likely to be hospitalized than
placebo
✓ -RR<1 patients with paxlovid less likely to get hospitalized than placebo
Relative Risk reduction (RRR):
✓ -proportionate reduction in risk for the intervention group relative to
refrence group
✓ -RRR = ( risk for reference group - risk for intervention -group / risk for
refrence group ) x 100
✓ -Interpretation example: RRR= 88.8837%, paxlovid groups risk of HOD is
reduced by 88.9% relative to the placebo group
✓ -Reference = placebo group
✓ -Intervention = paxlovid
How was alpha =0.05 determined?
Master01 | September, 2024/2025 | Latest update
, 1 | P a g e | © copyright 2024/2025 | Grade A+
✓ -R.A. Fisher wrote a book in 1925 he put statistical tables used to
determine statistical significance
✓ -Needed a separate table for each df which was too many
✓ -He chose alpha= 0.05
✓ -Is arbitrary, feels reasonable, it works, socially accepted
✓ -intended as a first look
✓ -If alpha = 0.02 that means there is a 2% chance of making a type one
error. Decreasing type one error we increase the chance of a type two
error ( missing significant findings )
Using Alpha and Null Hypothesis significance Testing( NHST)
✓ -Caused by the p-value there is dichotomy( 2 outcomes ) which are
significant p< alpha and non significant p> alpha
✓ -Significant also called positive findings ( most published)
✓ -non significant also called negative findings (put in the file drawer)
Importance of negative findings
Master01 | September, 2024/2025 | Latest update
