Statistic Assignment Paper Help

Statistic

Suppose that you are following a group of children for the development of asthma over a one- year period. You identify 100 children on January 1st, screen them for asthma, and set up a monitoring program to check on their status on a monthly basis. Five children are considered prevalent cases because they were diagnosed with asthma before January 1st. Ten children develop asthma on March 1st and another ten children develop asthma on July 1st. Another 10 children who remain healthy were followed for six months and then were lost to follow-up. All of the remaining children did not develop asthma and were not lost   to follow-up. Follow-up ended on December 31st.

•        1. What was the prevalence of asthma on June 1st?

5+10/100= 15/100 Answer: 0.15 or 15%

 

•        2. What was the prevalence of asthma on September 1st?

25/100 (10lost to follow up) 25/90= 0.277

 

•        3.How many person-months of observation were accrued by this population?

•        4.What was the incidence rate of asthma in this population for the one-year period?

20/100(-10 lost to follow up)

20/90=0.222

 Suppose that you began a one-year study of tuberculosis (TB) in a subsidized housing community in the Lower East Side of New York City on January 1st, 2010. You enrolled 500 residents in your study and checked on their TB status on a monthly basis. At the start of your study on January 1st, you screened all 500 residents. Upon screening, you found that 20 of the healthy residents were immigrants who were vaccinated for TB and so were not at risk. Another 30 residents already had existing cases of TB on January 1st. On February 1st, 5 residents developed TB. On April 1st, 5 more residents developed TB. On June 1st, 10 healthy residents moved away from New York City were lost to follow-up. On July 1st, 10 of the residents who had existing TB on January 1st died from their disease. The study ended on December 31, 2010. Assume that once a person gets TB, they have it for the duration of the study, and assume that all remaining residents stayed healthy and were not lost to follow-up.

• Is the subsidized housing community in the Lower East Side of New York City a dynamic or fixed population? Briefly explain the rationale for your answer.

1.Answer: Dynamic

ü  The population is dynamic because the living/housing condition changes several times, (moved out and lost to follow up, some die, immigrants are no longer at risk).

ü  The living condition is constantly changing.

ü  The membership is based on a condition and is transient.

ü  Turn overs deu to moving out of New York City.

•        2. What was the prevalence of TB in the screened community on January 1st?

Answer: existing cases 30 divided by the total population in the sample= 30/500= 0.6 or 6% is the prevalence of TB in the screened community on Jan 1^st.

 

•       3.  What was the prevalence of TB on June 30th?

Answer: 30 existing case of Jan 1^st+5 from feb1st +5 from April 1^st=40/total population (minus 10 death lost to follow up) 40/490=0.081% or 8.1% was the prevalence of TB on June 30^th.

•      4.   What was the cumulative incidence of TB over the year?

Answer: 10 total of new cases/total population(-30 prevalent cases that already had TB because they are no longer at risk & also deduct the 20 immunized immigrants because they are no longer at risk) new total population now is 450

5. The cumulative incidence of TB over the year + 10/450=0.0222 or 2.22%

• Suppose that you wanted to calculate the incidence rate of TB in the study population. Calculate the amount of person-time that would go in the denominator of this incidence rate. Be sure to show your work.