Question

**Prenatal vitamins and Autism.** Researchers
studying the link between prenatal vitamin use and autism surveyed
the mothers of a random sample of children aged 24 - 60 months with
autism and conducted another separate random sample for children
with typical development. The table below shows the number of
mothers in each group who did and did not use prenatal vitamins
during the three months before pregnancy.

Prenatal Vitamin | Autism | Typical Development | Total |

No vitamin | 110 | 65 | 175 |

Vitamin | 141 | 158 | 299 |

Total | 251 | 223 | 474 |

Conduct the hypothesis test for the stated null and alternative. Use ?α = K and round numeric answers to four decimal places.

?0H0: The variables use of prenatal vitamins during the three months before pregnancy and autism are independent.

??HA: The variables use of prenatal vitamins during the three months before pregnancy and autism are not independent.

1. Enter the expected values for the hypothesis test in the table below, rounded to four decimal places.

Prenatal Vitamin | Autism | Typical Development |

No vitamin | ||

Vitamin |

2. Calculate the test statistic for this hypothesis test. ?2X2 =

3. Calculate the degrees of freedom for this hypothesis test.

4. Calculate the p-value for this hypothesis test. p-value =

5. Based on the p-value, we have:

**A.** little evidence

**B.** strong evidence

**C.** extremely strong evidence

**D.** very strong evidence

**E.** some evidence

that the null model is not a good fit for our observed data.

Answer #1

The statistical software output for this problem is :

Contingency table results:

Rows: Prenatal Vitamin

Columns: None

Cell format |
---|

Count (Expected count) |

Autism | Typical Development | Total | |
---|---|---|---|

No vitamin | 110 (92.6688) |
65 (82.3312) |
175 |

Vitamin | 141 (158.3312) |
158 (140.6688) |
299 |

Total | 251 | 223 | 474 |

Chi-Square test:

Statistic | DF | Value | P-value |
---|---|---|---|

Chi-square | 1 | 10.922088 | 0.001 |

Test statistics = 10.9221

Degrees of freedom = 1

P-value = 0.001

**D.** very strong evidence

Prenatal vitamins and Autism. Researchers
studying the link between prenatal vitamin use and autism surveyed
the mothers of a random sample of children aged 24 - 60 months with
autism and conducted another separate random sample for children
with typical development. The table below shows the number of
mothers in each group who did and did not use prenatal vitamins
during the three months before pregnancy.
Prenatal Vitamin
Autism
Typical Development
Total
No vitamin
112
66
178
Vitamin
143
161...

Prenatal vitamins and Autism. Researchers
studying the link between prenatal vitamin use and autism surveyed
the mothers of a random sample of children aged 24 - 60 months with
autism and conducted another separate random sample for children
with typical development. The table below shows the number of
mothers in each group who did and did not use prenatal vitamins
during the three months before pregnancy.
Prenatal Vitamin
Autism
Typical Development
Total
No vitamin
109
63
172
Vitamin
138
156...

Prenatal
vitamins and Autism. Researchers studying the link between
prenatal vitamin use and autism surveyed the mothers of a random
sample of children aged 24 - 60 months with autism and conducted
another separate random sample for children with typical
development. The table below shows the number of mothers in each
group who did and did not use prenatal vitamins during the three
months before pregnancy.
Prenatal Vitamin
Autism
Typical Development
Total
No vitamin
108
64
172
Vitamin
138
155...

Prenatal vitamins and Autism. Researchers
studying the link between prenatal vitamin use and autism surveyed
the mothers of a random sample of children aged 24 - 60 months with
autism and conducted another separate random sample for children
with typical development. The table below shows the number of
mothers in each group who did and did not use prenatal vitamins
during the three months before pregnancy.
Prenatal Vitamin
Autism
Typical Development
Total
No vitamin
116
67
183
Vitamin
146
165...

6.34 Prenatal vitamins and Autism: Researchers
studying the link between prenatal vitamin use and autism surveyed
the mothers of a random sample of children aged 24 - 60 months with
autism and conducted another separate random sample for children
with typical development. The table below shows the number of
mothers in each group who did and did not use prenatal vitamins
during the three months before pregnancy (periconceptional period).
(Schmidt, 2011)
Autism
Typical Development
Total
No vitamin
111
70
181...

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