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# practice data analysis essay

When submitting this file, include your full name, course, and section in the filename. HW5 JohnDoe 354B01 is an example.

Before beginning the homework assignments, make sure you have reviewed this module's/lesson week's and presentations, as well as the practice data analysis. Finish all of your analyses in SPSS, then copy and paste your results and graphs into your homework document file. Any written questions (such as the text-based questions or the APA Participants section) should be answered in the appropriate area of the same file.

When we standardize scores, we transform individual scores from different normal distributions to a common normal distribution with known (a) ,mean____, (b) standard deviation____, and (c) percentiles____. Define the central limit theorem as described in Nolan and Heinzen (2016).

Answer: Refers to how a distribution of sample means is a more normal distribution than a distribution of scores, even when the population distribution is not normal.

3)

A z-score can be thought of as the number of _Standard Deviation_ that a score is from the mean.

4)

The formula for the standard error is the _standard deviation for the population_______ divided by the _square root of the sample__. (Use words, not symbols, to answer this question.)

5) Calculating z scores from raw scores: If a population has a mean of m=30 and a standard deviation of s = 3, calculate z scores for each of the following raw scores (X) from this population. Show work on the right hand side, put answers on the left in the space provided.

5a) X = 31; Z = Answer 0.3

Work: (31-30)/3=0.3

5b) X = 27; Z = Answer -1

Work: (27-30)/3= -1

5c) X = 37; Z = Answer 2.3

Work: (37-30)/3= 2.3

5d) X = 25.5; Z = Answer -1.5

Work: (25.5-30)/3= -1.5

6) Calculating raw scores from z scores: If a population has a mean of m=30 and a standard deviation of s = 3, calculate raw scores (X) for each of the following z scores from this population. Show work on the right hand side, put answers on the left in the space provided.

6a) Z = .57; X = Answer 31.71

Work: (0.57×3)+30=31.71

6b) Z = -2.03; X = Answer 23.91

Work: (-2.03×3)+30=23.91

6c) Z = -1.0; X = Answer 27

Work: (-1×3)+30=27

6d) Z = 1.68; X = Answer 35.04

Work: (1.68×3)+30=35.04

7) In a normal curve, what percentage of scores falls:

7a) Above the mean? Answer 50%

Work: where, s is the standard deviation.

7b) Between the mean and +1 standard deviation (SD) above the mean? Answer 34%

Work:

7c) In the left “tail” of the distribution, more than -2 SD from the mean. Answer (47.5%)

Work:

8) Compute the standard error (sm) for each of the following sample sizes, assuming a population mean m = 50 and a standard deviation of s = 4.5.

Work:

Work:

Work:

9) Compute a z-statistic for each of the following sample means, assuming m = 85 and s = 9 (Remember to compute sM before computing the z statistic!)

9a) A sample of 46 scores has a mean of 89 Answer 3.0145

Work:

9b) A sample of 82 scores has a mean of 76 Answer -9.4340

Work:

9c) A sample of 100 scores has a mean of 86. Answer 1.1111

Work:

Part II: SPSS Analysis

Be sure you have viewed the SPSS tutorial presentation before proceeding.

Open “Module 5 Exercise File 1” (found in the course’s Assignment Instructions SPSS folder) in order to complete these exercises.

Reminder: Be sure to paste in the SPSS output and write out the answers in the spaces given.

Part II: Questions 1a-1d

Open Module 5 Exerise File 1. It contains the IQ scores of 38 participants.

Compute descriptive statistics of the raw IQ scores

Create a histogram of the raw IQ scores

Transform the raw scores to z-scores following the method in the SPSS tutorial and text

Be sure to save this transformed file, since you will be using it next week as well.

Identify the z-score that is closest to 0 and farthest from 0.

Evaluate whether the scores are normally distributed.

1a)

Compute Descriptive statistics for the raw IQ scores and paste the table below.

Descriptive Statistics

Gender

N

Range

Minimum

Maximum

Sum

Mean

Std. Deviation

Men

High School GPA Scores

46

3.00

1.00

4.00

116.27

2.5276

.92214

College GPA Scores

46

1.77

1.17

2.94

103.65

2.2533

.39929

Valid N (listwise)

46

Women

High School GPA Scores

44

2.94

1.06

4.00

112.14

2.5486

.82349

College GPA Scores

44

1.40

2.05

3.45

120.19

2.7316

.36598

Valid N (listwise)

44

1b)

Create a histogram of the raw IQ scores and paste it below.

1c)

Using the descriptives method covered in the presentation and chapter, transform the IQ raw scores to z-scores, creating a new variable.

What is the z-score that is closest to 0 (on either side of the mean) in the data set?

What is the z-score that is the farthest from 0 (on either side of the mean) in the data set?

Answer: 2.48 and 2.54 when using the college GPA scores.

Answer: 1.17 and 3.45 when using the college GPA scores.

1d)

Based on the histogram from (1b) and your other answers above, would you describe the IQ data as being normally distributed? Why or why not? Support your answer with information from the chapter and presentations regarding normal distributions.

Answer: No, it is not entirely symmetric.

Justification: This is because there is the presence of a long tail to the left than o the right. However, we may conclude that the data presented in the histogram is moderately symmentric.

Part III: SPSS Data Entry and Analysis

Data provided below.

Stress Index Scores

101

60

10

27

89

60

16

184

34

17

78

141

11

104

76

65

87

19

126

98

Part III: Questions 1a-1d

The data in the column to the left represent Stress Index (SI) scores of a sample of 20 high-level business executives. In the general population, this Stress Index is normally distributed and has a mean of 60.2 and a standard deviation of 27.1. Enter this data into SPSS.

Generate descriptive statistics for this variable.

Generate a histogram for this variable.

In your data set, standardize the SI scores by transforming them into z-scores

SPSS will automatically name the new variable.

Which z-scores corresponds to a raw SI score of 60, 104, and 184?

Does the distribution reflect the distribution in the general population?

1-a)

Generate descriptive statistics for this variable.

Descriptive Statistics

N

Range

Minimum

Maximum

Sum

Mean

Std. Deviation

Stress Index Score

20

174.00

10.00

184.00

1403.00

70.1500

47.90371

Valid N (listwise)

20

1-b)

Generate a histogram for this variable.

1-c)

In your data set, standardize the SI scores by transforming them into z-scores under a new variable “ZSI.” Using your data set as a reference, what z-score corresponds to a raw SI score of 60?

To a raw SI score of 104? To a raw SI score of 184?

60

104

184

1-d)

Based on what you have been told about SI scores in the beginning of the problem,

does this sample’s distribution seem to reflect the distribution of SI scores in the general population?

Why or why not?

Answer: The sample distribution does not reflect the scores in the general population.

Justification: This is because the data is not normally distributed as evident in the hstoram above. Besides, there are two peaks in the histogram one on the lower left side and the other in the middle of the graph. Moreover, the large value of the standard deviation reveals that the data deviates more away from the mean.

Part IV: Cumulative

Data provided below for respective questions.

Part IV: Question 1a-1d (Non-SPSS)

A counselor wants to find out whether adding a Bible study component to treatment leads to different scores on a measure of generalized anxiety as compared to treatment without a Bible study component.

He assigns clents to 1 of 2 groups:

Group 1 participates in treatment plus a Bible study component.

Group 2 participates in standard treatment without the Bible study component.

1-a)

What is the independent variable in this experiment?

The use of the Bible

1-b)

What is the dependent variable?

Generalized anxiety

1-c)

What is the likely null hypothesis for this experiment?

Adding a Bible to treatment has no effect on the measurement score of generalized anxiety patients

1-d)

What is the likely research hypothesis for this experiment?

Adding a Bible to treatment has an effect on the measurement score of generalized anxiety patients

Diagnosis

Narcissism

1

1

1

1

1

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

33

12

20

26

27

9

17

27

34

32

12

8

18

12

6

5

8

14

10

6

Part IV: Questions 2a & 2b (SPSS)

A forensic psychologist wants to examine the level of narcissistic personality traits in those who are diagnosed with antisocial personality disorder (ASPD) and those who do not qualify for ASPD within a local prison population. She administers a measure of narcissistic personality traits where higher scores indicate higher levels of narcissism and scores range from 0–35.

Create a new SPSS data file for these scores.

Name your variables in Variable View. Assign values to the “Diagnosis” variable as follows: 1 = ASPD; 2 = no ASPD

Be sure to assign the correct level of measurement to each variable in the “Measure” column. Then return to Data View to enter the data.

Compute descriptive statistics by diagnosis (that is, for each of the two groups in one table) using similar steps to those covered in Green and Salkind’s Lesson 21, Section 4 and in the Module 3 SPSS presentation (“High School GPA scores by Gender”).

Construct a boxplot to show the difference between the 2 groups

2-a)

Compute descriptive statistics by diagnosis (that is, for each of the two groups in one table) (2 pts)

Answer: SPSS Table- Descriptive Statistics for Score (level of narcissistic personality) grouped by Diagnosis (ASPD/No ASPD):

Descriptive Statistics

Diagnosis

N

Range

Minimum

Maximum

Sum

Mean

Std. Deviation

ASPD

Narcissism

10

25.00

9.00

34.00

237.00

23.7000

8.81980

Valid N (listwise)

10

no ASPD

Narcissism

10

13.00

5.00

18.00

99.00

9.9000

4.12176

Valid N (listwise)

10

2-b)

Construct a boxplot to show the difference between the scores of the 2 groups. (3 pts)

Submit Homework 5 by 11:59 p.m. (ET) on Monday of Module/Week 5. Remember to name file appropriately.

Done!