Question

Given a mean of 259 and a standard deviation of 229.1, what is the z-score of the value 78 rounded to the nearest tenth?

Answer 1

z- score = -0.8

Explanation:

Given a mean of 259 and a standard deviation of 229.1

`z-score = (x-mean)/(standard deviation)`

x= 78

mean= 259

standard deviation = 229.1

Plug in all the values

`z-score = (78-259)/(229.1)`

`z-score = (-181)/(229.1)`

z-score = -0.7900480

z- score = -0.8

Answer 2

The formula for z-score is given by:
z=(x-μ)/σ
where;
μ=mean
σ=standard deviation
thus;
z=(78-259)/229.1
z=-0.790048
z=0.8