A sample of n = 4 scores is obtained from a population with μ = 70 and σ = 8.If the sample mean corresponds to a z-score of 2.00,what is the value of the sample mean?
A)M = 86
B)M = 78
C)M = 74
D)M = 72

Question

Quizplus · Accepted Answer

The z-score formula when applied to a sample mean is z = (M - μ) / (σ/√n), where M is the sample mean, μ is the population mean, σ is the population standard deviation, and n is the sample size. Given z = 2.00, μ = 70, σ = 8, and n = 4, we solve for M: 2 = (M - 70) / (8/√4) => 2 = (M - 70) / 4 => M = 78.

A Sample of N = 4 Scores Is Obtained from a Population