(Solved):   3) In a certain bell-shaped population the mean salary was 4500 and the standard deviation ...

 

3) In a certain bell-shaped population the mean salary was 4500 and the standard deviation was 250 . What is the percentage elements that are between the salaries 4000 and 4750? a. Approximately \( 68 \% \) b. Approximately \( 81.5 \% \) c. Approximately \( 34 \% \) d. Approximately \( 47.5 \% \) 4) For the following data set, find the sample variance of the variable \( y \). a. \( s_{y}^{2}=6.67 \) b. \( s_{y}^{2}=2.58 \) c. \( s_{y}^{2}=5 \) d. \( s_{y}^{2}=2.24 \)