Assume that a voltage level between 123.0 and 125.0 volts is randomly selected. what is the probability that the selested voltage level is greater than 124.0?

To answer this question, first let us define that probability is:

 Probability = number of favorable outcomes / total number of outcomes

In this case we want to select 124.1V to 125V so:

number of favorable outcomes = 10

Since the total range is between 123.0V to 125.0V:

total number of outcomes = 20

Therefore:

Probability = 10/20

Probability = 0.50

This means that 50% of the time, the voltage will be greater than 124.0V                                                               

a. the residual plot for model 1 has a random pattern and is a good fit for the data.