Question 3

Use the information in nhanes1.sav to answer the following questions. You should use SPSS to calculate any sample statistics you will need to do this question, but for part (c) you are required to do the rest of the calculations by hand, using a calculator.

The researcher is interested to see whether there is a difference in initial systolic blood pressure (BPXSY1) between those people reducing fat in their diet and those who aren’t.

(a) Use an appropriate graph to compare the distribution of initial systolic blood pressure (BPXSY1) for those reducing fat in their diet and those who aren’t. Label the axes correctly, include unit of measure and provide an appropriate title with your NAME included.

(b) Using the graph produced in part (a), briefly describe the two distributions.

(c) Using an appropriate statistical test, determine if, on average, there is a difference in initial systolic blood pressure (BPXSY1) between those people reducing fat in their diet and those who aren’t. In performing the test, include:

i. State appropriate hypotheses (define any symbols used).

ii. Using an appropriate formula and showing all working, calculate a suitable test statistic. You can use SPSS to calculate the means and standard deviations but the test statistic should be calculated by hand.

iii. Without using SPSS, calculate the P-value of this test (clearly define the degrees of freedom used in calculating this value).

iv. Interpret the P value and write a meaningful conclusion to answer the above question.

(d) Estimate, with 90% confidence, the true mean difference in initial systolic blood pressure (BPXSY1) between those people reducing fat in their diet and those who aren’t.

 Ensure you explain the confidence interval in context of the problem.

Assignment-Data-Set