Statistical Methods Flashcards
7 cards from real CQIA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Statistical Methods flashcards as text
What is the purpose of stratification in data analysis?
Answer: To separate data into subgroups to identify patterns
Stratification divides data into meaningful subgroups (by shift, machine, operator) to reveal hidden patterns.
An X-bar chart is used to monitor which characteristic of a process?
Answer: The average (mean) of subgroup measurements
An X-bar chart tracks the subgroup average over time to detect shifts in process centering.
Which statistical tool displays the frequency distribution of continuous data?
Answer: Histogram
A histogram displays how continuous data is distributed across intervals (bins), showing shape and spread.
The interquartile range (IQR) is calculated as:
Answer: Third quartile minus first quartile
IQR = Q3 − Q1, representing the spread of the middle 50% of data and is resistant to outliers.
A c-chart is most appropriate when:
Answer: Counting defects per unit with constant sample size
The c-chart monitors the count of defects per unit when the opportunity for defects is constant.
Process capability index Cpk differs from Cp because Cpk:
Answer: Accounts for both spread and process centering
Cpk accounts for how centered the process is relative to specification limits, while Cp only considers spread.
Which of the following best describes a Type II error in hypothesis testing?
Answer: Failing to reject a false null hypothesis
A Type II error (beta error) occurs when you fail to detect a real effect — accepting a false null hypothesis.