6. a) Distinguish between: i. Chance causes and assignable causes ii. Variables and attributes 8M b)


6. a) Distinguish between:
i. Chance causes and assignable causes
ii. Variables and attributes
8M
b) The subjoined are the neglect results of 10 lots, each lot life 300 items. Number
defectives in each lot are 25, 30, 35, 40, 45, 35, 40, 30, 20 and 50. Calculate the average
fraction short and three sigma limits for P-chart and set-forth whether the rule is in
control.