A statistics class wants to apply a one-sample t-interval to estimate mean homework time.
Which condition is NOT required for the t-procedure to be valid?
- Acheck_circle
The population standard deviation is known.
- B
The population is approximately normal or n is large.
- C
The sample is random.
- D
Observations are independent.
Explanation
The t-procedure is used precisely when sigma is unknown; the conditions are random, independent, and normal/large.