Question

According to a census company,10.1%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. She randomly selected 240 births for which the mother was 35 to 39 years old and found 28 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 0.101, compute the expected number oflow-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____

(b) Answer the obstetrician's question at the α=0.10 level of significance using the chi-square goodness-of-fit test. State the null and alternative hypotheses for this test.

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.

A.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 α=0.10 level of significance.

B. Reject the null hypothesis. There is not 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 α=0.10 level of significance.

C.Do not 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 α=0.10 level of significance.

D. Do not reject the null hypothesis. There is not 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 α=0.10 level of significance.

(c)Answer the obstetrician's question at the α=0.10 level of significance using a z-test for a population proportion. State the null and alternative hypotheses for this test.

Use technology to compute the P-value for this test

State a conclusion for this test in the context of the obstetrician's question. Choose the correct answer below.

A. Reject the null hypothesis. There is not 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 α=0.10 level of significance.

B. Do not 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 α=0.10 level of significance.

C. Do not reject the null hypothesis. There is not 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 α=0.10 level of significance.

D. 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 α=0.10 level of significance.

Answer #1

The mean birth weight of male babies born to 121 mothers taking
a vitamin supplement is
3.633.63
kilograms with a standard deviation of
0.630.63
kilogram. Use a 0.05 significance level to test the claim that
the mean birth weight of all babies born to mothers taking the
vitamin supplement is equal to 3.39 kilograms, which is the mean
for the population of all male babies.
State the null and alternative hypotheses. Find the z-score and
the P value and make...

Based on the National Center of Health Statistics, the
proportion of babies born at low birth weight (below 2,500 grams)
in the United States is roughly .078, or 7.8% (based on all the
births in the United States in the year 2002). A study was done in
order to check whether pregnant women exposed regularly to second
hand smoke increases the risk of low birth weight. In other words,
the researchers wanted to check whether the proportion of babies
born...

Previously, 5% of mothers smoked more than 21 cigarettes during
their pregnancy. An obstetrician believes that the percentage of
mothers who smoke 21 cigarettes or more is less than 5% today. She
randomly selects 145 pregnant mothers and finds that 4 of them
smoked 21 or more cigarettes during pregnancy. Test the
researcher's statement at the α=0.05 level of significance.
What are the null and alternative hypotheses?
H0:p =0.05 versus H1: p <0.05
(Type integers or decimals. Do not round.)...

A scientist has read that the mean birth weight, ?, of babies
born at full term is 7.4 pounds. The scientist, believing that ? is
different from this value, plans to perform a statistical test. She
selects a random sample of birth weights of babies born at full
term and finds the mean of the sample to be 7.1 pounds and the
standard deviation to be 1.8 pounds.
Based on this information answer the following questions
What are the null...

Previously,
4%
of mothers smoked more than 21 cigarettes during their
pregnancy. An obstetrician believes that the percentage of mothers
who smoke 21 cigarettes or more is less than
4%
today. She randomly selects
125125
pregnant mothers and finds that
4
of them smoked 21 or more cigarettes during pregnancy. Test the
researcher's statement at the
alpha equals 0.05α=0.05
level of significance.
What are the null and alternative hypotheses?
Upper H 0H0:
muμ
equals=
nothing versus
Upper H 1H1:
muμ...

Low-birth-weight babies are at increased risk of respiratory
infections in the first few months of life and have low liver
stores of vitamin A. In a randomized, double-blind experiment, 55
low-birth-weight babies were randomly divided into two groups.
Subjects in group 1 (treatment group, n1 = 30) were given 25,000 IU
of vitamin A on study days 1, 4, and 8; study day 1 was between 36
and 60 hours after delivery. Subjects in group 2 (control group, n2
=...

Randomly selected birth records were obtained, and categorized
as listed in the table to the right. Use a 0.01 significance level
to test the reasonable claim that births occur with equal frequency
on the different days of the week. How might the apparent lower
frequencies on Saturday and Sunday be explained?
Day
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Number of Births
50
58
65
64
59
56
35
Determine the null and alternative
hypotheses:
Calculate the test statistic X2...

15% of all college students volunteer their time. Is the
percentage of college students who are volunteers larger for
students receiving financial aid? Of the 354 randomly selected
students who receive financial aid, 60 of them volunteered their
time. What can be concluded at the α = 0.10 level of significance?
For this study, we should use The null and alternative hypotheses
would be: H 0 : (please enter a decimal) H 1 : (Please enter a
decimal) The test...

Education influences attitude and lifestyle. Differences in
education are a big factor in the "generation gap." Is the younger
generation really better educated? Large surveys of people age 65
and older were taken in n1 = 37 U.S. cities. The sample mean for
these cities showed that x1 = 15.2% of the older adults had
attended college. Large surveys of young adults (age 25 - 34) were
taken in n2 = 38 U.S. cities. The sample mean for these cities...

births
Mean: 359666.67
standard Deviation: 16864.88
n= 12
Determine if there is sufficient evidence to conclude the
average amount of births is over 5000 in the United States and
territories at the 0.05 level of significance.
Clearly state a null and alternative hypothesis
Give the value of the test statistic
Report the P-Value
Clearly state your conclusion (Reject the Null or Fail to
Reject the Null)
Explain what your conclusion means in context of the data.

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