# Thread: Z-scores for probability in tails

1. ## Z-scores for probability in tails

I haven't done any stats in years and now I am in a course for my grad program and I am so lost. My teacher is very confusing and I am trying my best to make sense of the way of going about finding z-scores in probability in tails. Do anyone know a good place that would illustrate the way to use the table and what the values of the tables are in layman's terms?

This is the type of problem that I am having problems with:

Trying to find the z-score for which a total probability of .02 falls more than z standard deviations (in either direction) from the mean, that is below mean-zo or mean+zo. Not sure how to type special characters but the o = standard deviations.

If anyone could help, I would greatly appreciate it. Getting past this type of problem would be huge for me.

Thanks,

Rich

2. For the probability of 96&#37; ( 2% plus or minus ), Z is 2.05.
Please also note that Z scores for 99%, 95%, 90%, and 80% are 2.59, 1.96,1.64 and 1.28 respectively.

3. Dear, for total probability of 2 &#37; total area within +or- 2*sigma will be 98%.Z value corresponding to 98% is 2.33

4. Originally Posted by dmmarathe
Dear, for total probability of 2 % total area within +or- 2*sigma will be 98%.Z value corresponding to 98% is 2.33
I have taken into account 2 on left tail and 2 on right tail, which make 4 resulting in a confidence level of 96%. This is what I felt with my limited knowledge.

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