Project #86930 - Biostatistics assignment

Directions: Before you begin, save this form (FILE, SAVE AS: M4A2_Midterm Exam_Your First and Last Name). Read scenarios 1 -8, and then answer questions 1—50. In order to receive full credit, you must copy and paste a screen captured image of your data output file from the statistical software that was used to compute the answer. To generate a screen capture image, press ALT + Prt Scr. Save your work frequently to your computer. Once you are ready to submit your work, click Browse My Computer and find your file. Once you've located your file click Open and, if successful, the file name will appear under the Attached files heading. Scroll to the bottom of the page, click Submit and you're done. Be sure to check your work and correct any spelling or grammatical errors before you post.



Scenario 1:
Answer the following multiple choice questions (1-6). Type out your answer in the space provided, include both the letter and the selection. Questions 7-10 are true or false. Type out your answer in the space provided.  

 

  1. A subset of a population selected to help make inferences on a population is called?

    1. A population

    2. A census

    3. Inferential statistics

    4. A sample

Answer:

  1. Which of the following is true for a normally distributed data set

    1. Mean < Median < Mode

    2. Mode < Median < Mean

    3. Mean = Median = Mode

    4. Median < Mode < Mean

Answer:

 

  1. In a 5 x 7 contingency table, the degrees of freedom are?

    1. 35

    2. 24

    3. 30

    4. 28

Answer:

 

  1. The difference between observed and expected frequencies is measured by what statistic?

    1. Chi-Square, X2

    2. ANOVA

    3. 2 sample z-test

    4. 2 sample t-test


Answer:

 



 

  1. In using ANOVA,

    1. It is possible to determine exactly which population means differ from the others

    2. It is assumed that the population distributions are not normal

    3. It is assumed that the population variances are unknown but unequal

    4. It is assumed that the samples are independent.


Answer:

 

  1. The sample statistic is the point estimate of

    1. The population standard deviation, σ.

    2. The population median.

    3. The population mean, μ.

    4. The population mode.


Answer:

  1. If there are outliers, then the mean will be greater than the median.

True or False: Answer:_____________


  1. Standard deviation is the square of variance.

True or False: Answer:_____________


  1. The mean is the 50th percentile of any normal distribution.
    True or False: Answer:_____________


  2. The Fisher Exact test should be used when the expected frequency is below 5.
    True or False: Answer:_____________

 

Scenario 2:

A researcher wants to determine if different forms of regular exercise alter low-density lipoprotein (LDL) also referred to as “bad cholesterol,” levels in overweight middle aged females between the ages of 35 and 45.  Participants in the study are randomly assigned to one of four exercise groups - resistance training, aerobic exercise or stretching/yoga – and instructed to follow the program for 8 weeks.  Their LDL levels are measured after 8 weeks and are summarized below. Run the test at a 5% level of significance.  

 

Exercise Group

N

Mean
(mg/dl)

SD
(mg/dl)

No exercise (TV watching 60 min/day)

20

240

7.5

Resistance Training 60min/day

20

217

7.3

Aerobic Exercise 60min/day

20

200

6.8

Stretching/Yoga

60min/day

20

238

7.0

 

  1. What is the null hypothesis equation for this experiment?


  2. Fill in the following table. LDL levels can assume any value within a given range. Ex (199.7, 200.1, 201.0)

Variables

Continuous vs. Discrete

Qualitative vs. Quantitative

Scale of Measurement:
Nominal, Ordinal, Interval, Ratio

LDL Levels (mg/dl)

  1. Continuous

  • Quantitative

  • Ratio

 

  1. What is the statistical test that you will use?

    1. t-test

    2. One way ANOVA

    3. Two way ANOVA

    4. Chi-square

Answer:

  1. Specify whether you accept or reject the null hypothesis? Run the test at a 5% level of significance.  
    Answer:















Scenario 3:

What is the 25th, 50th, and 75th percentile for Drug 1 (3pts)

Drug 1.

Drug1

Percentile

1.03

0.11

  1. 25th percentile =


  2. 50th percentile =


  3. 75th percentile =

0.74

0.4

1.66

0.57

0.11

0.74

1.07

1.03

1.93

1.07

0.40

1.66

0.57

1.93

2.45

2.45



Scenario 4:
What is the mean, median, and mode for the following data set 1:

 

Data set 1

 
 

4

Paste your output file below

 

3

 
 

6

 

5

 

3

 

7

Mean

 

Median

 

Mode

 



Scenario 5:
Triglycerides are digested fat that is circulating in the blood. They provide energy to the body. Following an 8 hour fast, elevated triglyceride levels have been linked to a greater chance for heart disease. A researcher wants to determine if an experimental drug lowers triglyceride levels (mg/dL) in individuals with elevated triglycerides. Her data is summarized in the table below. Run the test at a 5% level of significance.  

N

Placebo

Standard Drug

Experimental drug

1

167.3

106.1

166.1

2

169.0

107.8

167.8

3

169.9

108.7

168.7

4

170.8

109.6

169.6

5

171.7

110.5

170.5

6

171.6

111.4

174.4

7

172.5

111.3

171.3

8

172.4

112.2

175.2

9

173.3

112.1

172.1

10

173.2

113.0

176.0

11

174.5

114.3

177.3

12

175.7

115.5

178.5

13

177.0

116.8

168.8

14

177.6

117.4

165.4

15

179.1

118.9

178.9


  

  1. What is the null hypothesis equation for this experiment?




  2. Fill in the following table

Variables

Continuous vs. Discrete

Qualitative vs. Quantitative

Scale of Measurement:
Nominal, Ordinal, Interval, Ratio

Triglyceride Levels

     
  • What is the statistical test that you will use?

    1. t-test

    2. One way ANOVA

    3. Two way ANOVA

    4. Chi-square

Answer:

  1. Specify whether you accept or reject the null hypothesis? Run the test at a 5% level of significance.  
    Please paste your data output file in the area below.
    Answer:

 

Perform multiple pairwise comparisons on the data from Scenario 6, with the Bonferroni Adjusted t-test to determine what groups differ from one another.

Table 1

Answer questions 31-37 Remember to calculate the t-test statistic values by hand.  

  1. What is the value of  ?
    Answer: ______________
    Round to ten-thousandths decimal place: 0.0000
    (Hint   is located on the DATA output file)

Bonferroni

Comparison


Round to thousandths decimal place: 0.000



t-critical, v=42, P=0.050 = 2.018

j



Round to thousandths decimal place: 0.000

P<Pcrit
(YES OR NO)

1 vs 2
Placebo vs. Standard

   

1

0.017

 

1 vs 3
Placebo vs. Experimental

 

2

0.017

 

2 vs 3 Standard  vs. Experimental

 

3

0.017

 

Paste your data output file in the space below.  




















Scenario 6:

To determine the effectiveness of a new diuretic drug, urine output was measured in 12 men and 12 women, and compared to placebo control in 12 men and 12 women. The data are summarized in the table below. Run the test at a 5% level of significance.  

 

Mean
Urine Output
(mg/kg/hr)

SD

Placebo

1.58

0.66

Drug

1.98

0.77

 

  1. What is the null hypothesis equation for this experiment?


  2. What is the n value for Placebo?

  1. 24

  2. 12

  3. 48

  4. 1.58


Answer:

 

  1. What statistical test would you use?

    1. z-test

    2. Chi square X2

    3. t-test

    4. ANOVA

Answer:

  1. What is the t-critical value for this experiment (α = 0.05)? Use table 4-1 from the Primer of Biostatics 7th Ed. Text.
    Answer:

  2. Based on the statistical test that you chose, specify whether you accept or reject the null hypothesis at P<0.05?
    Please paste your data output file in the area below.

Answer:  

 

Scenario 7:

Researchers wanted to determine if insulin levels were different between men and women with type II diabetes. At the start of the study none of the individuals had type II diabetes. The average age of men was 46 years old, the average age of women was 47. The baseline insulin levels were 100.3 mg/dl in women, and 105.3 mg/dl in men. At the end of the study, 104 women had type II diabetes out of 2476 women studied, and 105 men had type II diabetes in the 1951 men studied. Run the test at a 5% level of significance.  

  

  1. What is the null hypothesis equation for this experiment?


  2. What statistical test would you use? z-test

  1. z-test

  2. Chi square X2

  3. Relative Risk

  4. Odds ratio

Answer:


  1. What proportion of women developed type II diabetes in this study?

Answer:

  1. What proportion of men developed type II diabetes in this study?

Answer:

  1. What is the z-critical value for this experiment (α = 0.05)? Use table 4-1 from the Primer of Biostatics 7th Ed. Text.
    Answer:

  2. Based on the statistical test that you chose, specify whether you accept or reject the null hypothesis? Run the test at a 5% level of significance.   Please paste your data output file in the area below.
    Answer:


 

Scenario 8:

You have been tasked with collecting pilot data for a research study where you hypothesized that people with metabolic syndrome will also have elevated blood glucose levels. The data is summarized in the table below. Run the test at a 5% level of significance.  

Metabolic Syndrome

Normal Blood Glucose

Elevated Blood Glucose

YES

3

10

NO

11

4



  1. What statistical test would you use?

  1. Yates Correction

  2. Chi square X2

  3. Relative Risk

  4. Fisher Exact test

Answer:

  1. Based on the statistical test that you chose, specify whether you accept or reject the null hypothesis? Run the test at a 5% level of significance.  

Please paste your data output file in the area below.

Answer




Subject Mathematics
Due By (Pacific Time) 10/17/2015 12:00 am
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