Answer:
a) 106
b) 53
Step-by-step explanation:
Minimum required medical files can be found using the formula
n≥ p×(1-p) × where
- n is the minimum required medical files
- p is the estimated proportion for blood type b
- z is the corresponding z-score for two tailed 85% confidence level
- ME is the margin of error in the estimation
For the case (a)
If there is no preliminary estimate for p, then it is estimated as p=0.5
corresponding z-score for two tailed 85% confidence level is 1.44
and ME is 0.07.
Putting all in the formula;
n≥ 0.5×0.5 × ≈ 106
For the case (b)
The only difference is p=≈0.144
n≥ 0.144×0.856 × ≈ 53