Answer:
2
Step-by-step explanation:
Value = 80
Mean = 70
Variance = 25
Standard deviation=root(Variance)=root(25)=5
z score = (value - mean)/standard deviation
= (80-70)/5
= 10/5
= 2
z-score using mean 70 and variance 25 is 2
Given :
A final statistics exam had a mean of 70 and a variance of 25
First we find out standard deviation using variance
standard deviation =[tex]\sqrt{variance} =\sqrt{25} =5[/tex]
Now we find out z-score
[tex]z-score =\frac{value - mean}{standard \; deviation }[/tex]
value =80
mean=70 and standard deviation =5
substitute all the values
[tex]z-score = \frac{80-70}{5} =2[/tex]
So, his z-score using mean and variance is 2
Learn more : brainly.com/question/10649097
