The percentage of infants delivered at less than 37 weeks gestation was 12.7% in

Question

The percentage of infants delivered at less than 37 weeks gestation was 12.7% in 2009 up from 10.6% the previous year at a local hospital. Has this upward continued? We are interested in testing whether the population proportion of preterm births has increased from 12.7%. A random sample of 400 births taken this year contained 57 preterm births.
1. What are the assumptions for this hypothesis test?
2. State the hypotheses.
3. Calculate the test statistic. Show the work with the formula.
4. Using the appropriate probability distribution, find the p-value. Show the work, do not just give a numerical value.
5. Assess the strength of the evidence against the null hypothesis by interpreting the p-value.
6. Using a statistical computing package such as Excel, Minitab, SPSS, or StatCrunch, copy and paste output for the hypothesis test.
7. Make the decision to reject or fail to reject the null hypothesis. Explain how you arrive at the decision.
8. Write the conclusion to the hypothesis test in context.

Explanation / Answer

Test statistic is (.1425-.127)/sqrt(.127*(1-.127)/400) (57/400= .1425) Test statistic is 0.93, which has a p value of .1762, (from z table) which isn't very significant (the problem doesn't tell you what level of significance to use). I assume you can do the rest.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.