Question 1193142
**1. Find the z-score for the given confidence level (c = 0.98)**

* Since c = 0.98, the alpha level (α) is 1 - 0.98 = 0.02.
* We need to find the z-score that corresponds to an area of 1 - α/2 = 0.99 in the standard normal distribution table.
* The z-score for 0.99 is approximately 2.33.

**2. Use the formula for sample size (n)**

* The formula to determine the minimum sample size (n) needed to estimate the population standard deviation (σ) with a given confidence level and margin of error (E) is:

   n = (z * σ / E)² 

   where:
      * n is the sample size
      * z is the z-score corresponding to the desired confidence level
      * σ is the population standard deviation
      * E is the desired margin of error

* Substitute the given values:

   n = (2.33 * 6.9 / 2)² 
   n = (16.077 / 2)² 
   n = 8.0385² 
   n ≈ 64.62

**3. Round up to the nearest whole number**

* Since we need a whole number of samples, round up n to 65.

**Therefore, the minimum sample size (n) needed to estimate sigma for the given values is 65.**