Describe t-distributions.
-In a metal fabrication process, metal rods are produced to a specified target length of
15 feet. Suppose that the lengths are normally distributed. A quality control specialist
Collects a random sample of 16 rods and finds the sample mean length to be 14.8 feet and
A standard deviation of 0.65 feet. Which of the following statement is true?
A) The sampling distribution for the sample mean follows the t-distribution with 16 degrees of freedom.
B) The sampling distribution for the sample mean follows the t-distribution with 15 degrees of freedom.
C) The mean of the sampling distribution for the sample mean is 14.8 feet.
D) The sampling distribution for the sample mean is Normal with a mean of 14.8 feet and standard deviation of .65 feet.
E) The standard error is 0.65 feet.

Question

Quizplus · Accepted Answer

The t-distribution is used when the sample size is small (n < 30) and the population standard deviation is unknown. The degrees of freedom for the t-distribution is n-1, which in this case is 16-1 = 15.

Describe T-Distributions. -In a Metal Fabrication Process, Metal Rods Are Produced to Produced