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1) You conduct a well-designed study involving a random sample

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1) You conduct a well-designed study involving a random sample. Your analysis shows this sample is normally distributed and representative of the population; however, the mean age in the sample is 29.4 years, and the mean age in the population is 30 years. What is this type of difference called, and what is the likely cause of the difference? Should the researcher be concerned?

2) You would like to know the average wait time of adult patients seen in federally funded health clinics in the United States. You randomly select 100 clinics and then collect the wait time for 100 randomly selected patient visits. What type of sample is this? Is it a probability or nonprobability sample?

3) You decide to start again comparing the wait time at your clinic this year versus last year, this time programing SPSS to select every 14th patient each year. What type of sample is this? Is it a probability or nonprobability sample?

4) You would like to compare the wait time at your clinic this year versus last year. Your electronic medical record database contains the check-in time and rooming time for all patients seen in the last 2 years. You import the data into your SPSS statistics program and program the computer to select randomly 500 patients seen last year and 500 patients seen this year. What type of sample is this? Is it a probability or nonprobability sampling method?

5) If one of the hospitals in your sample was the regional Women’s and Children’s Hospital, would you expect the mean hemoglobin level collected at that hospital to be different from that of the other hospitals?

6) 1) What is the difference between probability and nonprobability sampling? 2) Identify whether probability or nonprobability sampling is utilized for each entry in the following list: Convenience sampling Cluster sampling Simple random sampling Quota sampling Systematic sampling Stratified sampling

7) You are studying a new screening instrument and determine the following after screening 135 people. Of the 60 individuals who are known to have the disease, 58 screen positive. One person without the disease screens positive. Seventy-four people without the disease screen negative. What is the efficiency of the screening test? 98% 96% 99% 44%

8) You have developed a new buccal swab test for hepatitis C and enroll 1,388 subjects to test the screen. There are 941 people who do not have hepatitis C and test negative with your screen. There are 388 people who test positive with your screen. There are 435 subjects with confirmed cases of hepatitis C, and 59 test negative. Complete the appropriate 2 × 2 table and use it to answer the following questions.

9) Melanomas are the deadliest form of skin cancer, affecting more than 53,000 Americans each year and killing more than 7,000 annually. Your state currently has 167 cases of melanoma reported, and there are 1,420,000 people in the state. What is the prevalence rate in your state?

10) 1) What happens to the efficacy of the screen when the prevalence rates go down? 2) Why might you consider lengthening the time between screens or developing a more specific screen with the new prevalence rate?