Check my answers please!

Thanks a lot.

Five students reported that the previous night they slept: 7,8,7,10,9 hours.
Calculate the sample varience and standard deviation.

sample varience = 1346.5

standard deviation = 36.7

Consider this. Ths standard deviation can never be larger than the range of scores. Assuming that you are still talking in hours, you answer is much larger.

mean = 8.2

Differences obtained by subtracting the score from the mean =
1.2
.2
1.2
-1.8
-.8

Squaring each of these gives you

1.44
.04
1.44
3.24
.64

Totaling 6.8. Dividing this by N (5) gives you 1.36 = variance

The square root of the variance is the standard deviation.

I hope this helps. Thanks for asking.