Question

ch 3* the proportion of observations from a standard normal distribution (z) that take values less than -1.25 is about
0.1056
0.1151
0.8849

Explanation:

Step1: Use standard - normal table

We use the standard - normal table (z - table) to find $P(Z < - 1.25)$. The z - table gives the cumulative distribution function values for the standard normal distribution $Z\sim N(0,1)$.

Step2: Look up the value

In the standard - normal table, we find the row corresponding to $-1.2$ and the column corresponding to $0.05$. The value in the table at this intersection is the probability $P(Z < - 1.25)$. Looking up the value in the z - table, we get $P(Z < - 1.25)=0.1056$.

Answer:

A. 0.1056