# Thread: Why is Z0.05 = 1.645?

1. ## Why is Z0.05 = 1.645?

I'm using a standard normal table from back of my text, and I can't find 1.645 anywhere. If anything, shouldn't it be 0.4801? What am I missing? Please see the table I'm using for reference.. thank you

http://img340.imageshack.us/img340/8458/teste.jpg

2. Originally Posted by hanelliot
I'm using a standard normal table from back of my text, and I can't find 1.645 anywhere. If anything, shouldn't it be 0.4801? What am I missing? Please see the table I'm using for reference.. thank you

http://img340.imageshack.us/img340/8458/teste.jpg
You’re reading the table incorrectly. The value of p=0.4801 is the proportion of under the standard normal distribution that is to the right of a Z-score of 0.05.

Use (only) the first column on the left to obtain a Z-score…i.e. go down this column and look for 1.6 – then move to right to find the second decimal place 1.64 and subsequently obtain the proportion of the curve to right of this value which is approximatley 0.05

3. Thank you!

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