Answer
(a) 22.66%
(b) 20.38%
Work Step by Step
You will need this formula
$z = (y - μ) / σ $
Where
y = the point of intrest
μ = the mean of the data set
σ = the standard deviation of the data set
*Please refer to table 3 for the Standard Normal Cumulative Probability Table
Let Y represent a brain weight randomly chosen from population of Exercise 4.3.3. Find
(a) $Pr (Y\leq 1,325)$
$-0.75 = (1325 - 1400) / 100 $
$-0.75 = 0.2266$
(b) $Pr (1,475 \leq Y \leq 1,600)$
$0.75 = (1475 - 1400) / 100 $
$2 = (1600 - 1400) / 100 $
$0.75 = 0.7734$
$2 = 0.9772$
$0.9772 - 0.7734 = 0.2038$