Question

Accorcing to a census company, 7.1% of all babies born are of low birth weight. An obstetrician wanted to know whether mothers between the ages of 35 and 39 years give birth to a higher percentage of low-birth-weight babies. Sh randomly selected 280 births for which the mother was 35 to 39 years old and found 31 low-birth-weight babies. Complete parts (a) through (c) below. (a) If the proportion of low-birth-weight babies for mothers in this age group is 0.071, compute the expected number of low-birth-weight births to 35- to 39-year-old mothers. What is the expected number of births to mothers 35 to 39 years old that are not low birth weight? The expected number of low-birth-weight births to 35- to 39-year-old mothers is The expected number of births to mothers 35 to 39 years old that are not low birth weight is (Type integers or decimals.) (b) Answer the obstetrician's question at the a 0.05 level of significance using the chi-square goodness-of-fit test. State the null and altemative hypotheses for this test 071 на: 0.071 Н Use technology to compute the P-value for this test. Use the Tech Help button for further assistance. P-value Round to three decimal places as needed.) State a conclusion for this test in the context of the obstetrician's question. Choose the correct answer below. O A. Do not reject the null hypothesis. There is not sufficient evidence significance conclude that mothers between the ages of 35 and 39 years give blrth to a higher percentage of low-blrth welght bables at the u 0.05 level of O B. Reject the null hypothesis. There is not sufficlent evidence to conclude that mothers between the ages of 35 and 39 years give birth to a higher percentage of low-birth-weight bables at the a0.05 level of significance. O C. Reject the null hypothesis. There is sufficient evidence to conclude that mothers between the ages of 35 and 39 years give birth to a higher percentage of low-birth-weight babies at the 0.05 level of significance. Q D. conclude that mothers between the ages of 35 and 39 years give birth to a higher percentage of low-birth-weight babies at the a0.05 level of significance. Do not reject the null hypothesis. There is sufficient evidence 0.05 level of significance using a z-test for a population proportion. State the null and alternative hypotheses for this test (c) Answer the abstetrician's question at the 0.071 на Click to select your answer(s).

Answer 1

n=280 observed found low-birth-weight. babies = 31 con Found not low-birth-wieght babies= 280-31 = 249 (02) a) The expected number at low-birth-weight birthy is to -39 years. old mother is=hp=280x0.071 = (19.88] (ei) The expected number of births to mothers 35 to 39 years old that are not low birth weight is = n(1-6)=280x0.929= 1260 • 12 | () Ho: P1= Joo7| , + b > 0167 x=0.05 level of significance The Test statistic x² - 10i-eije (31-19:88) (249-26000 (Q . ) s (31-198833 260.12 e Concluso g? = 612900 +0.4754 = 16.6954 dof=2-1=1 ; p-value = 10.0097] = {0.010) ono ophion @ Reject the wall hypothesis. There is sufficient evidence to conclude that mothers between the ages of 35 and 39 year give to a higher percentage of Low-birth weight babies at the a=0.05 level of signticance. () Z-test Ho: Bel 0.01) P=. sample proportion = 2 = 3 1 Ho: Del 0.07) HPD0-071 = 0.1107 Pop Collo a The test statistic z 0.071X0.929 280 p-value = 10.0048 -0.005 conclusion: option . Reject the hull hypothesis. There is sufficient evidence to conclude that the mothers between ages of us to 39 years gives birth to a higher percentage of low-birth-weight babies at 2=0.05 level of significance.