$8.$ Variable is a product characteristic that is continues and can be measured.

$9.$ Fishbone diagram is non$-$statistical tool in SQC$.$

$10.$ The non$-$fulfillment of a requirement is called objective evidence.

$11.$ process capability Cp is more accurate than process capability Cok

$12.$ In a time series analysis it is often important to analyze seasonal variations.

$13.$ Seasonal variation almost always has a cyclical pattern in the data of several years. $14.$ A trend in a time series is a steady tendency to increase or to decrease over time.

$15.$ Sales of air conditioners follow a seasonal variation.

$16.$ A moving average of a time series is the value around which a series moves over time.