Question

In general, increasing the confidence level will narrow the confidence interval, and decreasing the confidence level widens the interval.

a. True
b. False

Answer 1

b. False

It is false since lowering the confidence level causes the interval to narrow while raising the confidence level actually widens it.

The chance or degree of assurance that the true population parameter will fall inside the estimated confidence interval is represented by the confidence level. A broader interval is needed to cover a greater range of possible values when the confidence level is raised, say from 90% to 95%. This is because a higher level of assurance is demanded. Conversely, lowering the level of confidence, for example, from 95% to 90%, allows for a lower level of certainty, which, in turn, allows for a narrower interval because it only needs to encompass a smaller range of possible values.