on a unit test in a statistics class, the teacher determines that the mean test grade was 77.5 with a…
on a unit test in a statistics class, the teacher determines that the mean test grade was 77.5 with a standard deviation of 5.2. one students test grade was 91. what is the z - score for the students test?\n-5.20\n-2.60\n2.60\n5.20
Answer
Answer:
C. 2.60
Explanation:
Step1: Recall z - score formula
The z - score formula is $z=\frac{x-\mu}{\sigma}$, where $x$ is the data point, $\mu$ is the mean, and $\sigma$ is the standard deviation.
Step2: Identify values
We have $x = 91$, $\mu=77.5$, and $\sigma = 5.2$.
Step3: Substitute values into formula
$z=\frac{91 - 77.5}{5.2}=\frac{13.5}{5.2}\approx2.60$