Suppose your statistics professor reports test grades as​ z-scores, and you got a score of 1.57 on an exam. ​a) Write a sentence

Answer:

a) In this case, we have a z-score of 1.57, characterized as:

This signifies that our score is 1.57 standard deviations above the average of all test scores.

b)

Using the normal standard distribution or Excel, we computed:

This represents 2.275% of the dataset.

Step-by-step explanation:

Previous concepts

Normal distribution denotes a "probability distribution that is symmetric around the mean, indicating that data close to the mean occurs more frequently than data further from it".

The Z-score serves as "a statistical measurement representing a value's relation to the average (mean) of a set, calculated in terms of standard deviations away from the mean".

Solution to the problem

Part a

For this instance, we hold a z-score of 1.57, which is defined as:

This shows that our score is 1.57 deviations above the overall test score average.

Part b

A z-score of z=-2 indicates that your friend's score is 2 deviations below the other test scores.

Assuming a normal distribution, we can derive the percentage:

Using the normal standard distribution or Excel, we discovered:

This represents 2.275% of the data.