Question

The z-score of an observation equal to 25 from a population with mean 50 and a standard deviation equals to 10 equals:

A.-3.5
B. -1.75
C. - 1.5
D. -2.5

Answer 1

The value is
`z = -2.5`

Explanation:

From the question we are told that

The the random selected observation
`x = 25`

The mean is
`\mu = 50`

The standard deviation is
`\sigma = 10`

Generally z score is mathematically represented as

`z = (x - \mu)/(\sigma )`

=>
`z = (25 - 50)/(10 )`

=>
`z = -2.5`