# Thread: help with calculating z-score.

1. ## help with calculating z-score.

Hello guys,
I have the answer here and need explanation on coming to terms with it. The question,

5000 apartments sold in a certain area and the mean price is $459,000 and the standard deviation is$76000. A particular apartment has a z-score of 3.78. What did it sell for? – The formula to calculate z-score is (x -mean) / standard deviation. The answer that I have from the text book is $459,000+3.78*76,000=$746,280… but why?

I've been punching in the numbers into the calculator and do not get $746,280. Any help is appreciated. Regards 2. ## Re: help with calculating z-score. BASIC MATH IDIOT MISTAKE... I should have did the multiplication before the addition. Originally Posted by schia Hello guys, I have the answer here and need explanation on coming to terms with it. The question, 5000 apartments sold in a certain area and the mean price is$459,000 and the standard deviation is $76000. A particular apartment has a z-score of 3.78. What did it sell for? – The formula to calculate z-score is (x -mean) / standard deviation. The answer that I have from the text book is$459,000+3.78*76,000=$746,280… but why? I've been punching in the numbers into the calculator and do not get$746,280.

Any help is appreciated.

Regards