Question

The following table gives the scores of 30 students in a mathematics examination.
Scores 90–99 80–89 70–79 60–69 50–59
Students 3 9 13 4 1
Find the mean and the standard deviation of the given data. Hint: Assume that all scores lying within a group interval take the middle value of that group. (Round your answers to two decimal places.)

I got found the mean, how do i find the standard deviation?

Answer 1

adding all together and then divide by the amount of data

Answer 2

I just got it, thanks!

Answer 3

welcome