Question

Find the standard deviation for the given sample data. Round your answer to one more decimal place than is present in the original data. Christine is currently taking college astronomy. The instructor often gives quizzes. On the past seven quizzes, Christine got the following scores: 55, 18, 39, 20, 20, 44, 69

Answer 1

Answer:

s = 19.7

Step-by-step explanation:

First we need to calculate the mean x' of the sample as:

$x'=\frac{55+18+39+20+20+44+69}{7}=37.9$

We sum all the scores and divide them by the number of scores.

Then, the standard deviation s is calculated as:

$s=\sqrt{\frac{(55-37.9)^2+(18-37.9)^2+(39-37.9)^2+(20-37.9)^2+(20-37.9)^2+(44-37.9)^2+(69-37.9)^2}{7-1} }\\ s=19.7$

We square every score less the mean, sum every value, then divide that by the number of scores less 1 and finally, we calculate the square root.

So, the standard deviation of the sample is 19.7