Question

John got 86 marks in this Statistics test. If the marks of the whole class had a mean of 62 and a standard deviation of 7, what was John’s standard score? (answer in two decimal places)​

Answer 1

Given:

John got 86 marks on this Statistics test. The marks of the whole class had a mean of 62 and a standard deviation of 7.

To find:

We have to find John's standard score.

Solution:

• The formula to find the standard score in statistics is=$z=\frac{x-\mu}{\sigma}$.
• Where z= standard score, x= marks got by John=86, μ= mean of the marks of the whole class=62, σ=standard deviation=7
• So, z=$\frac{86-62}{7}=\frac{24}{7}=3.43$
• So, the standard score of John in the Statistics test is 3.43 among the whole class.

Final answer:

John’s standard score is 3.43. [upto two decimal place]