Exercise for Z values

We will solve some simple problems to identify the area using z table.

Below image will tells you which Z table we need to use. z tables.

We need to look in to right z table as it is greater than mean 0.As per the table, the value is 0.4918 (look at the column 2.4 and column 0.00).

But we need to identify the area greater than 2.4, as we know the probability of left and right tail is 50% or 0.5 each.

Now P(Z>2.4) = 0.5 – 0.4918 = 0.0082

We still need to look in to right z table, When we need to calculate the area less than 2.4 which will also include left tail.shown below.

We need to look in to right z table as it is greater than mean 0.As per the table, the value is 0.4918 (look at the column 2.4 and column 0.00).

As we need to include the left tail which occupies 50% area

So, P(Z<2.4) = 0.5+0.498= 0.998

We need find the area greater than -1 which will also include right tail.As we need to find area from -1 we can have a look at left z table

We will calculate this area using both left and right z table.

Using left z table:

If we look at the column 1 and row 0.00 the value will be 0.8413, which will include the right tail area as well.

Using right z table:

If we look at column 1 and row 0.00 the value will be 0.3413 (obviously 0.8413-.05 ).Now we also need to include the left tail.

So , P(Z>-1) = 0.5+0.3413 = 0.8413

Published by viswateja3