Question

Does anyone know how to do this? (I am either doing it wrong or doing my math incorrectly)

Answer 1

i know how to do this

Answer 2

ok so, numbers are 4,13,5,6,9
If the mean of these data is approximately 7, what is the population standard deviation for these data? (Round the answer to the nearest tenth.)

Answer 3

The population standard deviation is defined as:
$$s = \sqrt{\frac 1 {N-1} \sum_{i=1}^N (x_i - \bar x)^2}$$

Answer 4

Ah, no, nevermind. 'Tis N, not N-1.

Answer 5

oh uh, sorry, but do you know what we plug into that equation?

Answer 6

N is the number of data values. Okay, so the simplified thing is:
#1.) Take the mean. We have that; it's 7. We have that N = 5.
#2.) Now we subtract the mean from each datum and square the result. Let's see:
4 - 7 = -3, 3^2 = 9
13 - 7 = 6, 6^2 = 36
5 - 7 = -2, 2^2 = 4
6 - 7 = -1, 1^1 = 1
9 - 7 = 2, 2^2 = 4
#3.) Now we take the mean of those values. 54/5, or 11.02.
#4.) Finally, we take the square root of the final product. sqrt(11.02) = ?

Answer 7

ohhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Answer 8

fail, that's what I forgot to do, take the square root, wow

Answer 9

thank-you so much