Can anyone explain the z-score in reference to statistics? I just don't get it!
2007-05-28 12:24:46 · 2 answers · asked by c'estmoi 6 in Education & Reference ➔ Homework Help
I have 30 bags of potato chips that are supposed be 12 oz.
The mean weight is 11.9 oz
the standard deviation is 0.4 oz
Does this mean anything to anyone??
2007-05-28 12:28:24 · update #1
The z-score is the number of standard deviations from the mean a particular example is.
For instance, your potato chip bags have a mean weight of 11.9 ounces and a standard deviation of 0.4 ounces. If you had a bag that weighed 12.3 ounces, that's one standard deviation away, so it has a z-score of 1. If you had one that weighed 11.5 ounces, it has a z-score of -1. If it weighed 12.5 ounces, that's 1.5 standard deviations higher, so it would have a z-score of 1.5.
2007-05-28 12:32:52 · answer #1 · answered by atomicjohnson 3 · 0⤊ 0⤋
subtract actual from expected and divide by standard deviation to get the Z-score.
(12.0 - 11.9) / 0.4 = 0.1 / 0.4 = .25 (Z-score)
That could occur randomly, so there's no statistically significant different between the actual and the expected.
2007-05-28 19:39:10 · answer #2 · answered by Steve A 7 · 0⤊ 0⤋