Hi! I have a sample (of 30) who’s outcome was measured binomially as either YES/NO. The expected population should have entirely NO answers. I therefore want to calculate if there is a significant difference in the proportions between sample of 23/30 (23-YES, 7-NO) and the expected proportion of 0/30 (0-YES, 30-NO). Is using a z-score calculator and finding the p-value a correct method even when one proportion is 0%? Can this method also be used if the different sample populations were compared with each other (ie 23/30 compared with 15/30)? Thank you!
Proportion Z-score calculator
- Thread starter Jaffacakes
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- Tags proportions significance spss
The normality assumption is usually reserved for when npq >= 10, where q = 1-p. That's my rule of thumb at least. When you get very high/low p's the distribution is less normal and exact calculations are preferred. I think the way to go about this is to create confidence intervals of p for both samples and see if they overlap.
Your Null hypothesis says that your data are collected from a population with a YES proportion of 0.00000000000... .
Obviously, you can reject that hypothesis as soon as you have just 1 YES observed in your sample.
AFAICS it makes no sense to ask how often a 23% rate would be observed in samples of size 30, if the population rate is assumed to be exactely zero.
With kind regards
Karabiner
Obviously, you can reject that hypothesis as soon as you have just 1 YES observed in your sample.
AFAICS it makes no sense to ask how often a 23% rate would be observed in samples of size 30, if the population rate is assumed to be exactely zero.
With kind regards
Karabiner