# Project: A Research Project on Birth Weight

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Assignment 4: Statistical Inference on Population Mean

(Put your answers in this document and submit it through Blackboard Assignment Dropbox.)

Part 1: Confidence Interval Estimation

A Research Project on Birth Weight

The data file

(SPSS) or (EXCEL)

is a sample of birth records taken by the North Carolina State Center for Health and Environmental Statistics. The data set represents a sample of around a thousand births taken within the state of North Carolina. Of particular interest will be incidents of Low Infant Birth Weight. Low birth weight has been associated with weaker development of many characteristics such as intelligence, coordination, strength, etc. Low birth weight is commonly defined as less than 2500 grams (approximately 88 ounces).

The variables examined are:

|sex: |Sex of child (1=Male, 0=Female) |

|race: |Race of child (0=other Nonwhite, 1=White, 2=Black, 3=American Indian,  4=Chinese, 5=Japanese, 6=Hawaiian, |

| |7=Filipino, 8=Other)  |

|mothage: |Age of mother, in years |

|mothed: |Education level of mother, in years |

|gest: |Completed Weeks of Gestation, in weeks |

|marital: |Marital status (1=married, 0=not married) |

|cigs: |Smoking Cigarette (1=Smoke, 0=Do not smoke) |

|drinks: |Drink Alcohol (1=Drink Alcohol, 0=Do not drink alcohol) |

|apgar1: |Apgar score at 1 minute (0-10) |

|fas: |Fetal Alcohol Syndrome (0=No, 1=Yes) |

|plural: |Number of children born of the pregnancy |

|totounc: |Birth Weight in total ounces |

|btotounc: |Birth Weight Categories (1=Below normal birth weight, 0=Normal birth weight) |

Data values are labeled in the SPSS data file provided above.

The data was from North Carolina State Center for Health Statistics. The data for this project came from 1995 birth registry at the North Carolina State Center for Health and Environmental Statistics.  Use is allowed if reference is cited to the above agency.

The data used in this assignment is a random sample. Answer the questions in the next page and recode the data if it is necessary.

Use SPSS or other statistical software to answer the following questions from using the birth weight data. In the following question, the term population means the population of mothers who successfully gave birth to a child during the period of data collection. Use t-score (or t-distribution) for the following confidence interval estimations. The confidence interval estimate in SPSS Explore option is done by using t-score.

The following link has SPSS example for getting confidence interval for mean of a population:

The following link has SPSS instruction video for confidence interval for mean of a population:

Data File for part 1: (You can use either SPSS data or EXCEL data.)

SPSS:

EXCEL:

SPSS will give you the confidence intervals in interval form. You need to answer the questions below using both interval form and point estimate ( margin of error.

For example,

Interval form: ( 135, 145)

Point estimate ( margin of error: 140 ( 5

1. Find the 95% confidence interval for the average birth weight in the population.

Interval form: ( , )

Point estimate ( margin of error: ___________(__________

2. Find the 95% confidence interval for the average Apgar score in the population.

Interval form: ( , )

Point estimate ( margin of error: ___________(__________

3. Find the 95% confidence interval for the average birth weight from smoking mothers population.

Interval form: ( , )

Point estimate ( margin of error: ___________(__________

4. Find the 95% confidence interval for the average birth weight from nonsmoking mothers population.

Interval form: ( , )

Point estimate ( margin of error: ___________(__________

5. Write few paragraphs to interpret the statistics that you found from questions 1 through 4.

Part 2: Hypothesis Test for Mean

Adam claimed that his average morning pulse rate is 65. A group of his friends do not think so and they took a random sample of 12 morning pulse rates from Adam on 12 randomly selected days. The data is the following: 70, 67, 67, 68, 66, 72, 75, 68, 68, 66, 68, 69.

The following link has an SPSS example for performing the one-sample t-test:

The following link has an SPSS instruction video for performing the one-sample test:

The objective of this research is to see if Adam’s average morning pulse rate is different from 65 per minute. (Perform a one-sample t-test at 5% level of significance.)

Use the pulse rates data above to answer the following questions:

1)      State the null and the alternative hypotheses:

H0 (Null): __________

Ha (Alternative): __________

2)      Is the normality assumption valid? (Verify this using the p-value of the Shapiro-Wilk normality test.)

3)      What is the value of the t-test statistic: ___________

4)      What is the value of the p-value of the test: ___________

5)      Would you reject the null hypothesis? (Use the p-value of the t-test.)

6)      Draw a conclusion for this test:

7) Find the 95% confidence interval estimate for Adam’s average morning pulse rate.

________ ( ________

8) If one wishes to see if Adam’s average morning pulse rate is higher than 65, what would you conclude the analysis using the statistics above?

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