Surname(e.g. Straayer), Given Name(e.g. Dave), class mtg. time
In this worksheet we will examine the “WRI” data we gathered on our last worksheet. We will use our calculators, and some of the functions on them.
1.
Calculate the sum of the wrist sizes. 2 nd /Stat-List/Math/Sum( and then use 2 nd /Names to put in the name of the wrist list. Record that below under Sum:
2.
Count the number of wrists. Here are two ways: 2 nd /Stat-list/Ops/Dim( as above. Do this and record the number below under n(dim). Next, use Stat/Edit, find the WRI list, and press up-arrow TWICE to get to the BOTTOM of the list. The calculator will actually stop on the first empty cell. Either subtract one from the WRI(nn) number, or press up-arrow to display WRI(nn). Note it is the same number as returned by DIM(
3.
Divide the sum by the n to get the mean (average), and record it as Mean.
4.
Copy the list into L1: 2 nd /Stat-list/names, find WRI (going UP may be quicker than going DOWN). Press ENTER when the WRI list is highlighted. Then pres the STO> key (immediately above the ON key), and press 2 nd /2 to get a line that reads WRI -> L1, and press enter. This will make a temporary copy of the WRIst data in L1
5.
Press Stat/EDIT/SortA(, then 2 nd /2 to put L2 in the line, then press ENTER.
6.
Examine the resulting sorted list in the Stat/Edit editor. If n is odd:
The middle will be in (n+1)/2, and you can down-arrow to find the middle value. Record it as Median if n is even:
record the two values at the n/2 location, and the n/2+1 location. Add them and divide by 2. Record as median.
7.
Find the squares of all the deviations from the mean: (L1-{Mean}} 2 -> L2
8.
Add these up: Sum(L2)
9.
Divide this by n-1 notice as soon as you press the

key, the display is Ans /
10.
Take the square root 2 nd /X 2 (/2 nd /(-)ANS/Enter Record this as the standard deviation.
11.
Type STAT/CALC/1-Car Stats/ENTER and then put in either L1 or WRI. If you see a FreqList, make sure it is empty.
12.
Note that 𝑥̅ is the mean, and Sx is the standard deviation that you calculated. If not, you did something wrong.
13.
Down arrow until you get to the five-number summary on the next page.
Sum: _________________ n (dim): ______________________
Mean: ____________________________ Median: _________________________
Standard Deviation: __________________
Five-number summary:
Min: _____________ Q1: _______________ Median: ____________ Q3: ____________ Max: _____________