Question

Fission tracks are trails found in uranium-bearing minerals, left by fragments released during fission events. An article reports that fifteen tracks on one rock specimen had an average track length of 12 μm with a standard deviation of 2 μm. Assuming this to be a random sample from an approximately normal population, find a 99% confidence interval for the mean track length for this rock specimen. Round the answers to three decimal places.

Answer 1

Answer:

Mean track length for this rock specimen is between 10.463 and 13.537

Step-by-step explanation:

99% confidence interval for the mean track length for rock specimen can be calculated using the formula:

M±$\frac{t*s}{\sqrt{N}}$ where

• M is the average track length (12 μm) in the report
• t is the two tailed t-score in 99% confidence interval (2.977)
• s is the standard deviation of track lengths in the report (2 μm)
• N is the total number of tracks (15)

putting these numbers in the formula, we get confidence interval in 99% confidence as:

12±$\frac{2.977*2}{\sqrt{15}}$ =12±1.537

Therefore, mean track length for this rock specimen is between 10.463 and 13.537