If the population mean is assumed to be 20 and the sample standard deviation is 5,a score of 15 would have a Z-value of approximately:
A)+1.00
B)-7.00
C)-1.00
D)+5.00

Question

Quizplus · Accepted Answer

The formula for calculating the Z-value is:

Z = (X - μ) / (σ / sqrt(n))

Where:
X = the score in question (15 in this case)
μ = population mean (20 in this case)
σ = population standard deviation (unknown)
n = sample size (unknown)

Since we do not have information about the sample size, we cannot directly calculate the Z-value. However, we can use the formula to estimate the Z-value by assuming that the sample size is infinitely large (i.e. approaching the population size). This is known as the standard normal distribution.

Using this approach, we can estimate the Z-value as:

Z = (15 - 20) / (5 / sqrt(infinity)) ≈ -1.00

Therefore, the best choice is C.

If the Population Mean Is Assumed to Be 20 and the Sample