SPSS Hypothesis Testing

Instructions

For this assignment, you perform a two-sample independent t-test, an ANOVA, and a correlation analysis related to the

datasetthat has been utilized in the previous two modules. Import the data into SPSS or, if you correctly saved the data

file from the Module 4 and 5Assignments, you may open and use that saved file to complete this Assignment. Type your

answers to all questions directly into the worksheet, and paste the required output at the end of this document.

Submit this Application Assignment by Day 7 of Week 11.

Research Scenario

A researcher is interested in the effect of a new medication on serum cholesterol, HDL cholesterol, and glycosylated

hemoglobin of adults. The researcher randomly selects a sample of 40 (20 male and 20female) participants who have

been diagnosed with high cholesterol. Assuring equal distribution of males and females, the participants are randomly

assigned to one of two conditions (or groups): Following pretest measures of serum cholesterol (chol), high-density

lipoprotein cholesterol (HDL), and glycosylated hemoglobin (glyhb), the experimental group (Group 1) is given the

medication for a period of 6months while the control group (Group 2) is given a placebo. After the 6months,chol, HDL,

and glyhb are again measured.

The posttest data for each participant are provided in the Module 4 Application Assignment Data SetExcel fileand can be

found in the Module 6 Learning Resources. The codebook for the data provided is as follows:

AGE Age in years

SEX 1 =male, 2=female

GROUP 1 =medication, 2=placebo

CHNG_CHOL change in cholesterol from pretest to posttest

HDL High-density lipoprotein at posttest

GLYHB Glycosylated hemoglobin at posttest

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Step 1: Import the Microsoft Excel data file into SPSS or use the correct saved SPSS data file as noted in the instructions

above.

Step 2: Conduct an independent samples t-test to determine if there is a difference between Group 1 (medication) and

Group 2 (placebo) in terms of changes in cholesterol values. Note that the independent variable is GROUP, and the

dependent variable is CHNG_CHOL .For this analysis, choose a two-tailed test of significance. (Be sure to save your

output.)

Step 3: Conduct a between-subjects ANOVA to determine if there is a difference between sex (males vs. females) and

HDL. Note that the independent variable is SEX, and the dependent variable is HDL. For this analysis, choose a two-

tailed test of significance. (Be sure to save your output.)

Step 4: Conduct a Pearson correlation to determine if there is a relationship between HDL and GLYHB. For this analysis,

choose a two-tailed test of significance. (Be sure to save your output.)

Step 5: Review your SPSS output and answer each of the following questions:

From the independent samples t-test output:

A. What is the mean CHNG_CHOL for Group 1? ** -5.95**-.45

B. What is the CHNG_CHOL standard deviation for Group 1? ______4.095 C. What is the mean CHNG_CHOL for Group 2? ___

D. What is the CHNG_CHOL standard deviation for Group 2?

**– 5.376**

*___1.395 E. What is the calculated t-score (equal variances assumed)? ___*© 2014 Laureate Education, Inc. Page 3 of 6

F. What is the probability that the obtained t-score was simply due to chance as opposed to actual gender differences

[see “Sig (two-tailed)” on output]? _________0.00

G. If the probability associated with the obtained t-score is <0.05, we assume the results (difference in mean

CHNG_CHOL between groups) are much more likely due to the effects of the medication than to chance. In other

words, we would say the results are statistically significant. Are the results statistically significant (yes or no)?

_________No

From the ANOVA output:

H. What is the mean HDL for group males? _________40.85

I. What is the HDL standard deviation for males? _________7.788

J. What is the mean HDL for group females? _________49.30

K. What is the HDL standard deviation for females? _________7.477

L. What is the calculated F-value? __________12.251

M. What is the probability (noted as “Sig” on output) that the obtained F-value was simply due to chance as opposed

to actual gender differences? __________0.01

From the correlation output:

N. What is the Pearson correlation score for HDL and GLYHB? ** – 587** The direction of the correlation is

O. What is the direction of the correlation value and what does this mean? __

negative. This implies that as HDL increase, GLYHB decreases and vice versa is true

P. What is the probability for the obtained Pearson correlation score [see “Sig (two-tailed)” on output]? _significant at

0.01 (2-tailed)

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Q. If the probability associated with the Pearson correlation is <0.05, we assume a significant relationship. Is there a

significant relationship between HDL and GLYHB? _________No

Step 6: Paste all required SPSS output below.

T test

Group Statistics

GROUP N Mean Std. Deviation Std. Error Mean

CHNG_CHOL 1 20 -5.65 4.095 .916

2 20 -.45 1.395 .312

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Independent Samples Test

Levene’s Test for

Equality of Variances

t-test for Equality of Means

F Sig. t df Sig. (2-

tailed)

Mean

Difference

Std. Error

Difference

95% Confidence

Interval of the

Difference

Lower Upper

CHNG_CHO

L

Equal variances

assumed

13.247 .001 -5.376 38 .000 -5.200 .967 -7.158 -3.242

Equal variances not

assumed

-5.376 23.349 .000 -5.200 .967 -7.199 -3.201

One way ANOVA

Descriptive

HDL

N Mean Std. Deviation Std. Error 95% Confidence Interval for Mean Minimum Maximum

Lower Bound Upper Bound

males 20 40.85 7.788 1.742 37.20 44.50 28 56

females 20 49.30 7.477 1.672 45.80 52.80 39 69

Total 40 45.08 8.666 1.370 42.30 47.85 28 69

ANOVA

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HDL

Sum of Squares df Mean Square F Sig.

Between Groups 714.025 1 714.025 12.251 .001

Within Groups 2214.750 38 58.283

Total 2928.775 39

Correlations

HDL GLYHB

HDL Pearson Correlation 1 -.587 **

Sig. (2-tailed) .000

N 40 40

GLYHB Pearson Correlation -.587 ** 1

Sig. (2-tailed) .000

N 40 40

**. Correlation is significant at the 0.01 level (2-tailed).