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WCU ECO 251 - ECO 251 Graded Assignment 1

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251grass1 1/18/08 (Open this document in 'Page Layout' view!) Name: Class days and time: Student NumberGraded Assignment 1Neatness counts on all assignments, as does the quality of your writeups. Staple your pages! Write onone side. Pleas ask me about any parts that you find confusing and/or wrong.1) Problem: Make sure that your student number is easily readable. Choose one of the columns below using the second to last digit of your Student Number. Example: Ima Badrisk has student number 123456;so she picks column x5. Using the computational formula, find the sample standard deviation of the data in the column that you have chosen: Also find the median and the third quartile. Show your work! Write on one side of the paper. Row x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 1 2.3 8.8 12.1 5.7 16.0 11.4 3.3 -2.5 6.7 3.0 2 7.9 2.9 3.6 5.7 3.5 -4.6 3.5 1.6 1.7 5.3 3 11.5 2.5 1.8 2.8 -1.7 4.7 12.2 2.7 2.0 1.1 4 2.1 6.5 9.9 2.9 6.8 -2.7 -1.6 -0.8 10.5 6.0 5 9.1 3.4 9.8 1.2 8.9 -3.6 7.1 -0.3 4.6 8.9 6 5.8 -3.6 6.8 6.8 4.1 -0.5 4.1 3.0 11.3 7.4 7 2.7 3.4 3.9 0.3 -2.9 -1.2 0.1 0.3 6.7 1.2 8 12.0 -1.5 9.9 9.6 15.5 -2.6 7.1 10.6 4.1 0.6 9 0.6 11.5 8.2 3.8 1.9 13.4 -1.5 4.9 5.2 4.2 10 -8.7 16.1 14.1 0.7 -0.9 0.5 1.0 3.3 3.7 7.1 11 4.1 4.6 6.8 9.3 3.0 3.2 6.2 14.8 9.9 5.0 12 -0.6 1.4 13.9 9.4 2.8 9.1 1.7 17.4 4.9 -2.5 13 -0.4 4.4 6.7 6.1 4.1 0.8 -2.3 9.5 9.7 8.8To get credit for the remainder of this assignment you must turn in original spreadsheets.2) This Computer Assignment has as its goal to do most of Problem G3 (not G3A) using Excel. Problem G3 appears on page 69 of the Supplementary Materials and Tables and a solution has been posted.Step 1: Open up an Excel worksheet and start by filling locations A1-14 by labeling the column with: the word "Class" in A1, the labels for the classes in A2 to A13, the word "Total" in A14. If you have trouble with some of these labels, using single quotes can help.Step 2: Put the abbreviation "Mdpt" for midpoint in B1. Fill Column B with the midpoints for the classes by putting 2.5 in B2 and 7.5 in B3. Highlight B2 and B3 and drag the fill handle down to fill the cells down to B13. (To do this point to the highlighted area until you get a black cross, then move the pointer down.) You should now have the numbers 2.5 to 57.5 in column B.Step 3: You now need the frequency column. Put "f” in C1. Copy the frequencies in C2 through C13. Highlight cell C14 and find the AutoSum logo, which is simply a summation sign  on the top. Clickon the summation sign and "enter." This will give you the sum of the frequencies. Remember thatnf .Step 4: Now compute the cumulative frequencies in column D. Head the column with "F" and copy the number from C2 to D2. In D3 put "=D2+C3." In D4 put "=D3+C4." Now highlight D3 and D4 and use the fill handle to fill in D5 through D13. The last cumulative frequency in D13 should be 90.251grass1 1/18/08 (Open this document in 'Page Layout' view!)Step 5: Label column E with "xf” or "fx." To compute this column, put "=B2*C2" in E2 and "=B3*C3" in E3. Use the fill handle to fill in the rest of the products down to E13. Use the AutoSum feature to put a total  fx in E14.Step 6: In column F you will compute fx2 or2fx. Label the column "xsqf” or "fxsq." Now F2 will be done with "=B2*E2," and F3 with “=B3*E3" and you can fill the column down to F13 with the fill handle, and get its sum  2fx using AutoSum.Step 7: Now compute the mean, variance and standard deviation using the computational formulas. In K1 put the words "n =" and copy n into L1, perhaps by writing "=C14" in L1. In K2 put the words "Mean =," and in L2 compute nfxx by using "=E14/C14." Now you are ready to do1222nxnfxs. Put "Var =" in K3. Remember that 2fx is in F14, n is in C14 and x is in L2. You should compute 2x by multiplying the mean by itself, so the formula in L3 should be "= (F14-C14*L2*L2)/ (C14-1)." You should get 132.5843. Now you need the standard deviation, which is simply the square root of the variance, so put "StDev =" in K4 and "=SQRT (L3)" in L4.Step 8: Now we are going to use the definitional formula to compute the skewness. Start by writing the value that you got for the mean in cell M2. Do not copy this value or use an equation to get it into M2, justtype it in. Excel will mess up some calculations if you do. Use the fill handle to fill the M column with themean. You are now going to compute  xx ,  xxf ,  2xxf  and  3xxf  in columns G, H, I and J. Head these columns with "x' ," "'fx'," "fx'sq" and "fx'cu." In G2 enter "=B2-M2" and use the fill handle to put the values of the midpoints minus the mean in G2 through G13. In H2 enter "=G2*C2, " use the fillhandle to fill in to H13 and use AutoSum to put the sum of column H in H14. This sum should be zero. In I2 enter "=G2*H2" and use the fill handle again. In I14 get  2xxf. You can use this to check the accuracy of your variance computation. In J2 enter "=G2*I2" and again fill the column. Use AutoSum to get  3xxf in J14. Then in cell K5 type "K3 =," and in L5 compute   3321xxfnnnk by typing "=C14*J14/((C14-1)*(C14-2)) Step 9: Use the formatting toolbar to center the first row of columns B through J. Make any other formatting changes that you think would improve the legibility of the spreadsheet and print out the results.3) Research Assignment. Talk to about 20 students. Ask them how many hours they studied over the last week. Use Excel to analyze your data. Put a heading in cell A1 and your data below it. Use the "Tools"pull-down menu. Pick "Data Analysis" and "Descriptive Statistics." (If you cannot find this, use Tools and Add-Ins to put in the analysis packs.) Check "Labels in First Row." and "Summary Statistics." Specify a range (like A1: A50) Comment on the output in a short paragraph. Are you close to the mean? Why or why not. The skewness statistic computed here is K3, so compute a measure of relative skewness and tell me if the data is highly skewed and in what direction. Write in brief literate English!4) Extra Credit (Don’t ask me for extra credit after you get a final grade that you don’t like. This is all there will be.)Do Problem G3 (from the Supplement


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