Finding Averages, Variances, and Standard Deviations

We will use the "Census Data" tab of the Lab 4 datasheet on an excel spreadsheet.

Here are our steps

1)Click on Cell B10

2)Choose "Formulas -> AutoSum -> Average", hit enter

3) To find the Residuals click on C2 and enter

=B2-B$10

Note:The $ operator fixes the location to be used when the formula is copy/pasted

4)Copy the formula in C2, Highlight the C2 to C8 Column and Paste

5)In D2 enter "=C2^2" to square the residuals

6)Copy past the D2 formula into D2 to D8

7)In D10 use "Formulas->AutoSum->Sum" to get the Sum of Squares

8)In D12 use "=D10/6", This is Variance = SSE/(n-1)

9)In D14 use "=SQRT(D12)", This is the Standard Deviation.

10)Use "Data->Data Analysis->Descriptive Statistics" on the data in column b

Questions

a) What is the mean population over the time frame?The Standard Deviation?

b)What is the 95% typical value interval?

c)How did your statistics compare to the Data Analysis in step 10?

"Census Data" tab of the Lab datasheet.

Year Population (x-) (x-)^2

1950 29885

1960 40663

1970 53766

1980 57890

1990 70745

2000 85806

2010 104769

Mean Sum Squared Error

Variance

Standard Deviation