For a standard normal distribution, find:

P(-1.28 < z < 0.8)

1. -15

2. 3

3. -15 3

4. Kindly refer to the attached image.

5. -45, This change represents that achieving the goal will reduced the time by 45 seconds.

Step-by-step explanation:

Given that it is a 5 kilometre race.

Time to be reduced each month = 15 seconds

Total number of months left in the race = 3

1. Riley wants to achieve each month a decrease of 15 seconds.

Integer representing the change = -15

2. Change in time i.e. 3 months is represented by integer 3.

3. There are a total of 3 months and there is a decrease of 15 every month.

so, multiplication expression is: -15 3

4. Kindly refer to the attached image for the number line representation of the answer.

The arrow is from 0 to -45.

5. Total change in time is -45.

This change represents that achieving the goal will reduced the time by 45 seconds.