A study was conducted to assess the effects that occur when children are exposed to cocaine before birth. Children were tested at age 4 for object assembly​ skill, which was described as​ "a task requiring​ visual-spatial skills related to mathematical​ competence." The 186 children born to cocaine users had a mean of 7.3 and a standard deviation of 2.9. The 186 children not exposed to cocaine had a mean score of 8.2 with a standard deviation of 2.9. Assume that the two samples are independent simple random samples selected from normally distributed​ populations, and do not assume that the population standard deviations are equal. Let population 1 be children born to cocaine users. Complete parts​ (a) and​ (b) below.

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A study was conducted to assess the effects that occur when children are exposed to cocaine before birth. Children were tested at age 4 for object assembly​ skill, which was described as​ "a task requiring​ visual-spatial skills related to mathematical​ competence." The 186 children born to cocaine users had a mean of 7.3 and a standard deviation of 2.9. The 186 children not exposed to cocaine had a mean score of 8.2 with a standard deviation of 2.9. Assume that the two samples are independent simple random samples selected from normally distributed​ populations, and do not assume that the population standard deviations are equal. Let population 1 be children born to cocaine users. Complete parts​ (a) and​ (b) below.
 
a. Use a 0.01 significance level to test the claim that prenatal cocaine exposure is associated with lower scores of​ four-year-old children on the test of object assembly.
 
Identify the null and alternative hypotheses.
 
 
A.
H0​:
μ1=μ2
H1​:
μ1>μ2
 
B.
H0​:
μ1<μ2
H1​:
μ1=μ2
 
C.
H0​:
μ1=μ2
H1​:
μ1≠μ2
 
D.
H0​:
μ1≠μ2
H1​:
μ1=μ2
 
E.
H0​:
μ1=μ2
H1​:
μ1<μ2
 
F.
H0​:
μ1>μ2
H1​:
μ1=μ2
 
What is the test statistic? 
 
​(Round to two decimal places as​ needed.)
What is the​ P-value?
 
​(Round to three decimal places as​ needed.)
State the conclusion for the test.
 
 
____ the null hypothesis. There ____ sufficient evidence to support the claim that prenatal cocaine exposure is associated with lower scores of​ four-year-old children on the test of object assembly.
 
b. Test the claim in part​ (a) by using a confidence interval.
 
The ____ confidence interval estimate is ______ <μ1−μ2< _______
​(Round to one decimal place as​ needed.)
 
Based on the confidence​ interval, is prenatal cocaine exposure associated with lower scores of​ four-year-old children on the test of object​ assembly?
 
____ since ___ _____ contained within the confidence​ interval, it
______ that prenatal cocaine exposure is associated with lower scores.
​(Type an integer or a decimal. Do not​ round.)
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