2. (1 pt) The following statement is true or false; When we know the population standard deviation, o, we use a standard normal
distribution (z-score) to calculate the error bound EBM and construct the
confidence interval and when the population standard deviation, o, is unknown,
we use a Student's t distribution (t-score) to calculate the error bound EBM and
construct the confidence interval.
a. true
b. false

If you know the population standard deviation (sigma), then you use the Z distribution. If sigma is not known, then you use the T distribution.

Side note: Even if sigma is not known, you could use the Z distribution if the sample size n is greater than 30. If n > 30, then the T distribution is approximately about the same as the Z distribution.

company a

step-by-step explanation:

using the linear regression models , it is found that company a   pays about $14 more. but using the same regression (linear) company b pays about $10 more.

so company a pays more than b

0.85% : )

step-by-step explanation: