What is the sample standard deviation?

Data Values Frequency
3.0 - 6.9 5
7.0 - 10.9 4
11.0 - 14.9 8
15.0 - 18.9 6
19.0 - 22.9 5

Question

What is the sample standard deviation?

Data Values	 Frequency 
 3.0 - 6.9	      5
 7.0 - 10.9	      4
 11.0 - 14.9	      8
 15.0 - 18.9	      6
 19.0 - 22.9	      5

amistre64 · Answer

$$variance=\frac{\sum(x-\bar x)^2}{n-1}$$

sd = $\sqrt{variance}$

amistre64 · Answer

find the mean

amistre64 · Answer

$$mean=\frac{\sum\ (5P(x_1)+4P(x_2)+8P(x_3)+6P(x_4)+5P(x_5))}{5+4+8+6+5}$$

amistre64 · Answer

where any given P(x) is the average of the class interval i believe

amistre64 · Answer

(5*4.95+4*35.8+8*12.95+6*16.95+5*20.95) = 478

478/28 =abt 17.0714

amistre64 · Answer

(5-17.0714)^2+(4-17.0714)^2+(8-17.0714)^2+(6-17.0714)^2+(5-17.0714)^2

 = 667.16509/27 = 24.71

sd = sqrt(24.71) = 4.971

if i recalled it correctly