I am not clear how to look for values in log table for example in question bank 4.27 probability is 0.99 value they have taken while solving the question is - 2.3263 from where does -2.3263 comes from? Thanks in advance.
We know that standard normal distribution is symmetric. So for the value of 99% , it can be written as the percentage point value of 1%(from page 162) of table book with a (minus) sign ,ie. -2.3263
Thanks alot. Could you please clarify a bit more on minus sign. Why to put minus sign here? And I was solving questions on upper and lower quartile just now. While looking for value of lower quartile from table (pg-162) for 25% they have not put minus sign befor the value but for 75% minus has been used. Why is that so?
Symmetric distribution means that equal weightage is given to both the areas under the curve. And since we don't have the percentage points for 99% probability, we take the 1% value with a minus sign.