# Descriptive Statistics: SPSS

Unit 1 Homework: Summarizing and Describing Data

This homework requires both SPSS and your calculator. There are very specific and helpful guidelines for doing this type of homework located in the Graphing Tutorial in Unit 1. Submit only one file for the entire homework into the gradebook. Either create text boxes in SPSS and type in your explanations and answers there, OR, do your work in Word, and cut and paste graphs and tables from SPSS into that document. APA format is required for figure and table captions. Remember that you must show your work to receive full credit.

In SPSS, create a database from the information in Table 1 (pg. 3) found at the end of this document. Use that information to answer questions 1 through3.

1. For the variable Math 201:

a. Create the appropriate graph (5 pts)

b. Create the appropriate descriptive statistics (5 pts)

c. What is the most appropriate descriptive statistic? Include the justification for your choices (5 pts)

d. Write out how you would explain this information to someone who had not had a course in statistics (5 pts).

2. For the variable Math Test:

a. Create the appropriate graph (5 pts)

b. Create the appropriate descriptive statistics (2.5 pts)

c. What is the most appropriate descriptive statistic? Include your justification for your choices. (2.5)

d. We know from experience that scores in the middle 50% of the distribution generally do well in our course in statistics. What scores would be the cutoffs for this range? (5 pts.)

e. Students who score below the 30th percentile on this test are referred to the Tutoring Center. How many should be referred?

(5 pts.)

3. For the variable Stat grade:

a. Create the appropriate graph (5 pts)

b. Create the appropriate descriptive statistics (2.5 pts)

c. What is the most appropriate descriptive statistic? Provide justification for your choices. (2.5)

d. What is the probability of finding a score of 90 or better? (5 pts.)

e. What scores mark the most deviant 10%? (5 pts.)

4. Reading readiness of preschoolers from an impoverished neighborhood (n = 20) was measured using a standardized test. Nationally, the mean on this test for preschoolers is 30.9, with s = 2.08.

a. Children below the 30th percentile are in need of special assistance prior to attending school. What score would indicate these children? (5 pts.)

b. What percentage of children score between 25 and 28.5? (5 pts.)

c. How many children would we expect to find with scores between 28 and 31.5? (5 pts.)

d. Children in the top 25% are considered accelerated readers and qualify for different placement in school. What score would mark the cutoff for such placement? (5 pts.)

5. Age at onset of dementia was determined for a sample of adults between the ages of 60 and 75. For 15 subjects, the results were Σx = 1008, and Σx2 =67878. Use this information to answer the following:.

a. What is the mean and s for this data? (5 pts.)

b. What is the percentile rank for an individual who shows dementia at age 62? (5 pts)

c. If we consider +/-1z to be the normal range of onset, what ages correspond to this? (5 pts.)

d. What ages identify the most deviant 20%? (5 pts.)

Table 1.

Student Database

ID # Gender GPA Math

201 Math

Test Stat

Grade

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Male

Male

Female

Female

Female

Male

Female

Female

Female

Female

Male

Male

Female

Female

Female

Female

Female

Female

Male

Female

Female

Female

Male

Male

Female

3.23

3.10

3.75

2.32

2.79

2.13

2.64

2.91

2.27

2.53

3.32

3.73

3.24

3.01

2.94

2.80

2.55

3.23

2.94

3.79

3.65

2.15

3.44

2.26

2.95

No

Yes

Yes

No

No

No

No

No

Yes

No

Yes

Yes

Yes

Yes

No

No

No

No

No

Yes

Yes

No

No

No

No

17

27

35

25

28

18

15

29

38

17

35

32

28

22

18

25

24

40

28

38

35

20

36

27

29 78

85

93

74

76

62

58

78

90

60

93

94

90

79

74

72

70

78

73

94

93

62

68

60

60

Description of Database

ID# Student identification number

Gender: 1 = male, 2 = female

GPA: Overall college grade point average

Math 201: Have you taken Math 201? 1 = No, 2 = Yes

Math Test: Score on a test of Math Skills

Stat Grade: Grade in introductory statistics course

A = 92 to 100

B = 82 to 91

C = 72 to 81

D = 62 to 71

F = 61 and below

See attached file.

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#### Solution Summary

The solution provides step by step method for the calculation of descriptive statistics in SPSS. Formula for the calculation and Interpretations of the results are also included.