The annual sales, in millions, for 28 toy department stores is listed.
A)Calculate the mean and standard deviation of the data. Answer to the nearest tenth.
B) Calculate the percent of sales to the nearest whole number, that are:
i)within one SD of the mean
ii)within two SD of the mean
"The annual sales, in millions, for 28 toy department stores is listed."
I don't see a list...
The folowing calculator link might help:
http://qudata.com/online/statcalc/
hit "clear", then enter your data on the left, then "calc"
If your data is not in ascending order of sales, hit "sort" so the second part of your question will be easier.
I get mean = 32.3
sigma = 6.45 so 2 sigma = 2*6.45 = 12'9
and here is your list ordered
mean - 12.9 = 19.4 , below your whole list
21.0
23.0
24.0
24.0
24.0
note here is mean - 6.45
27.0
27.0
27.0
27.0
29.0
31.0
32.0
note mean = 32.3
33.0
33.0
33.0
33.0
33.0
34.0
35.0
35.0
35.0
36.0
38.0
38.0
note - here is mean + 6.45
40.0
43.0
44.0
45.0
note - here is mean + 12.9 - below your list
your whole list is within 2 sigma of mean 100%
19/28 is within 1 sigma of mean
100 * 19/28 = 68% within 1 sigma