Question 2.6 (Textile Engineering & Fibre Science)
The average lea strength of a yarn is 50 kgf with a standard deviation of 5 kgf. How many tests must be made so that maen is estimated with % error or less than 1.96 with 95% level of confidence ?
| (A) | 10 |
| (B) | 50 |
| (C) | 100 |
| (D) | 200 |