Sample NMS Reference Report by YONTCHANG G - University of ...

WEEK 2 CHANCE OF CROP FAILURE
One proportion - binomial model
BINomial;stats 57 9;SIMple;EXAct
Binomial model, single sample
Sample size 57
Successes 9
Proportion 0.158
Approx s.e. of proportion = 0.048
Exact results:
95% confidence interval for prop. 0.075 to 0.279
Simple normal approximation:
95% confidence interval for prop. 0.063 to 0.253
The 95% confidence interval for the true risk of flooding with crop failure for the second week
in August is from 7.5% to 27.9%.
Estimated value (proportion) = 0.158 (15.8%)
s.e. = 0.048 (4.8%)
The risk of crop failure during week 2 of August is (9/57 = 0.1579): 15.79% or about 16%
with a return period of (1/0.1579 = 6.333) about 6.5 years. I am 95% confident that the
estimate of 15.8% is within ± 10.2% of the true risk of flooding with crop failure for the
second week.
WEEK 3 CHANCE OF CROP FAILURE
One proportion - binomial model
BINomial;stats 57 16;SIMple;EXAct
Binomial model, single sample
Sample size 57
Successes 16
Proportion 0.281
Approx s.e. of proportion = 0.060
Exact results:
95% confidence interval for prop. 0.170 to 0.415
Simple normal approximation:
95% confidence interval for prop. 0.164 to 0.397
The 95% confidence interval for the true risk of flooding with crop failure for the third week in
August is from 17% to 41.5%.
Estimated value (proportion) = 0.281 (28.1%)
s.e. = 0.06 (6%)
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