Bell-shaped Distribution?

[SmiileToday]

Data are drawn from a relatively symmetric and bell-shaped distribution with a mean of 110 and a standard deviation of 4. What percentage of the observations are less than 106? Thank you.

 

[guillermo]

X n(110; 4)

P(X 106) = P((X - 110)/4 (106 - 110)/4 ) = P(Z - 1) = 0.1587, answer!

 

[cidyah]

= 110
= 4
standardize x to z = (x - ) /
P(x < 106) = P( z < (106-110) / 4)
= P(z < -1) = 0.1587 (15.87 percent of the observations are less than 106)
(From Normal probability table)