Soc 3811 Basic Social Statistics First Midterm Exam Spring 2010 ANSWERS

Transcription

1 Soc 3811 Bac Socal Stattc Frt Mdterm Exam Sprng 010 ANSWERS INSTRUCTIONS: (A) Wrte your name on the lne at top front of every heet. (B) If you ue a page of note n takng th exam, gn & nert t nde th booklet before turnng n your exam. (C) Show your calculaton for numercal problem n the pace provded! Fll n the blank [1 pont each]: a. The graph of an contnuou varable called a(n). Htogram or polygon b. Decrptve tattc that decrbe the value mot typcal of the core n a frequency dtrbuton are called Meaure of central tendency. c. Varable lke EDUC and AGE, whch could have all poble numercal value n a gven nterval, are called. Contnuou d. A varable that clafe peron, object, or event nto two mutually excluve and exhautve categore called a(n). Dchotomy e. Many card game agn ncreang value to the four face card: Jack, Queen, Kng, Ace. What type of varable th? Orderable dcrete.

2 . Th table how repone to the 008 GSS varable THEISM, There a God who concern Hmelf wth every human beng peronally. Complete the lat two column of the table and report the modal category. [5 pont]: CATEGOR Frequency (f ) Percent (%) Vald Percent (%) Vald 1. Stongly agree Agree Nether agree nor dagree Dagree Strongly dagree Total 1,343 (66.4) Mng 0. IAP No anwer, don t know 1.1 Total 680 (33.6) TOTAL, Strongly agree MODE:

3 our name: 3. Th table dplay POLVIEWS n the 008 GSS. Calculate cumulatve frequence, vald percentage, cumulatve percentage, and report the medan. [5 pont]: DO OU THINK OF OURSELF AS LIBERAL OR CONSERVATIVE? Frequency (f) Cumulatve Frequency (cf) Vald Percent (%) Cumulatve Percent (c%) 1. Extremely lberal Lberal Slghtly lberal Moderate 740 1, Slghtly conervatve 68 1, Conervatve 37 1, Extremely conervatve 68 1, TOTAL 1, Don t Know No Anwer TOTAL, Moderate MEDIAN:

4 4. Calculate the Index of Dverty and Index of Qualtatve Varaton for th table howng 008 GSS varable SCISTUD, whch aked how well the repondent undertand the term centfc tudy. [5 pont] Frequency Percent Vald SCISTUD (f) (%) Percent (%) Vald 1. Clear undertandng General ene Lttle undertandng Total 1, Mng 9. IAP; DK, NA TOTAL, D 1 ( p 1 1 ( p p 3 ).09 ) IQV 3 31 K D K D: IQV:

5 our name: 5. Calculate the mean, medan, mode, and range of an ungrouped varable wth thee core. [5 pont] 1 = 3 4 = 5 7 = 7 = 5 5 = 9 8 = 5 3 = 7 6 = 11 9 = 11 Mode: 3, 5, 5, 5, 7, 7, 9, 11, 11 Medan: 3, 5, 5, 5, 7, 7, 9, 11, 11 N N Range: 11 3 = MODE: MEDIAN: MEAN: RANGE:

6 6. Now calculate the varance and tandard devaton for the ame ungrouped data n queton 5. [5 pont] 1 = 3 4 = 5 7 = 7 = 5 5 = 9 8 = 5 3 = 7 6 = 11 9 = 11 N 1 ( N 1 ) 1(3 7) 3(5 7) (7 7) 9 1 1(9 7) (11 7) VARIANCE: STAND. DEV.

7 our name: 7. Th table how how often people pray. Fnd the mode and medan. Then wrte an nterpretaton of thoe two central tendency tattc, explanng whch meaure more accurately decrbe how often people pray. [5 pont] HOW OFTEN DOES R PRA Frequency Percent Vald Percent Cumulatve Percent Vald 1. Never Le than once a week About 1- tme per year Several tme a year About once a month tme per month Nearly every week Every week Several tme a week Once a day Several tme a day Total 1, Mng 9. INAP, DK, NA TOTAL, MODE: 11. Several tme a day MEDIAN: 9. Several tme a week The mode the category wth the mot cae, but t occur n the hghet category th ordered varable dtrbuton. The medan the category that exactly dvde the dtrbuton n half (where the 50th percentle occur). The medan of everal tme a week more accurately repreent the typcal frequency becaue t occur cloer to the mddle of the varable value than doe everal tme a day.

8 Percent 8. Th graph, ung ung dfferent frequence than n problem #7, ha thee decrptve tattc for prayng: mean = 8.; medan = 10.0; varance = 11.. Calculate kewne and nterpret the graph hape, ncludng the type of kew. [5 pont] 30.0% 5.0% 0.0% 15.0% Mean Medan 10.0% 5.0% 0.0% NEVER EVER WEEK ONCE A DA ( Skew ABOUT ONCE OR TWICE A EAR LESS THAN ONCE A EAR Mdn) 3( ) TIMES A MONTH ABOUT ONCE A MONTH SEVERAL TIMES A EAR NEARL EVER WEEK HOW OFTEN DOES R PRA 1.61 SEVERAL TIMES A WEEK SEVERAL TIMES A DA INTERPRETATION: The dtrbuton ha a negatve kew, wth t tal to the left, becaue the mean prayng lower than the medan. Although the average prayng wa 8, half the ample prayed 10 or more tme.

9 9. Th table dplay the number of book bought by 60 tudent lat month. The mean Calculate the varance and tandard devaton for th grouped frequency dtrbuton. [5 pont] NUMBER OF BOOKS Score () Frequency (f) TOTAL 60 K 1 ( ) N 1 (f ) (1 3) (4 3) (4) ( 3) (5) (5 3) (13) (8) 60 1 (3 3) (30) VARIANCE: STAND. DEV.

10 10. The 008 GSS varable SIBS ( How many brother and ter dd you have? ) ha thee decrptve tattc for,01 repondent: mode = ; medan = 3; mean =3.6; range = 55; varance = 10.. Calculate the tandardzed core (Z core) for three repondent wth thee number of blng ( ). [5 pont] Z 1 Z Z Z Calculate the expeced number of blng ( ) for two repondent wth thee Z core. Z -0.4 Z ( ) ( 0.4)(3.19) Z ( ) (.)(3.196)