Answer:
[tex]z = 0.228[/tex]
Step-by-step explanation:
Given
x: -3 -1 0 1 1 2 4 4 5
n = 9
Required
Determine the z-score x = 2
z score is calculated by
[tex]z = \frac{x - Mean}{SD}[/tex]
First, we need to calculate the mean
[tex]Mean = \frac{\sum x}{n}[/tex]
Mean = \frac{-3- 1 + 0 + 1 + 1 + 2 + 4 + 4 +5}{n}
[tex]Mean = \frac{13}{9}[/tex]
[tex]Mean = 1.44[/tex]
Next is to calculate the standard deviation
[tex]SD = \frac{\sum (x_i - Mean)^2}{n}[/tex]
[tex]SD =\sqrt{ \frac{(-3-1.44)^2+(-1-1.44)^2+(0-1.44)^2+(1-1.44)^2+(1-1.44)^2+(2-1.44)^2+(4-1.44)^2+(4-1.44)^2+(5-1.44)^2}{9}[/tex][tex]SD =\sqrt{ \frac{(-4.44)^2+(-2.44)^2+(-1.44)^2+(-0.44)^2+(-0.44)^2+(0.56)^2+(2.56)^2+(2.56)^2+(3.56)^2}{9}[/tex]
[tex]SD =\sqrt{ \frac{19.7136+5.9536+2.0736+0.1936+0.1936+0.3136+6.5536+6.5536+12.6736}{9}[/tex]
[tex]SD =\sqrt{ \frac{54.2224}{9}[/tex]
[tex]SD =\sqrt{6.02471111111}[/tex]
[tex]SD = 2.455[/tex]
Substitute these values in
[tex]z = \frac{x - Mean}{SD}[/tex]
Where x = 2
[tex]z = \frac{2 - 1.44}{2.455}[/tex]
[tex]z = \frac{0.56}{2.455}[/tex]
[tex]z = 0.228[/tex]
Hence, the z score of x = 2 is o.228
