help 15,16,17

15. Which of the following is not true about the cause-and-effect criterion when estimating a cost function? A) Correlation of variables proves cause-and-effect B) Managers must be careful not to equate high correlation between two variables to mean that either variable causes the other C) Knowledge of operations can help managers discover cause-and-effect relationships D) Contractual arrangements may show a direct cause and effect between two variables E) none of the above 16. The conference method estimates cost functions A) using quantitative methods that can be very time consuming and costly B) based on analysis and opinions gathered from various departments C) using time-and-motion studies D) by mathematically analyzing the relationship between inputs and outputs in physical terms E) none of the above 17. The account analysis method estimates cost functions A) by classifying cost accounts as variable, fixed, or mixed based on qualitative analysis B) using time-and-motion studies C) at a high cost, which renders it seldom used D) in a manner that cannot be usefully combined with any other cost estimation methods E) none of the above