Chapter 8, Problem 41RE

To determine

To Find: The percentage of students that have finger span more than 10 inches.

Answer to Problem 41RE

The percentage of students having finger span more than 10 inches is $\text{1}.0\text{5}0\text{813 }\%$ .

Explanation of Solution

Given information: Use a large sample as much possible.

Lets take X as Finger Span (span of fully stretched hand from the tip of the pinky finger to the tip of the thumb), measured in the unit of inches.

Based on a sample of size (n) 50 , sample Mean =8.5 inches and Sample standard deviation =0.65 inches

Since sample size > 50

Approximate the distribution of X by a Normal distribution with Mean =8.5 inches and Standard deviation =0.65 inches

The probability that a randomly selected person’s finger span is more than 10 inches.

  $=\text{P}\left[\text{ X }>\text{1}0\right]=0.0\text{1}0\text{5}0\text{813}$

  

(Stat Crunch Steps :

to find $\text{P}\left[\text{ X }>\text{1}0\right]$

STAT > Calculators > Normal )

Hence the percentage of students who have finger span more than 10 inches

  $\begin{array}{l}=\left( \text{1}00\times \text{ P}\left[\text{X}>\text{1}0\right]\right)\\ =\left(\text{1}00\times 0.0\text{1}0\text{5}0\text{813}\right)\\ =\text{1}.0\text{5}0\text{813}\end{array}$

1.050813 % of students have finger span more than 10 inches .