Statistics

Please show detailed solutions.

Does cocaine use by pregnant women cause their babies to have low birth weight?
To study this question, birth weights of babies of women who tested positive for cocaine/crack during a drug-screening test were compared with the birth weights for babies whose mothers either tested negative or were not tested, a group we call "other"

Here are the summary statistics. The birth weight s are measured in grams.
Group n Sample mean Standard deviation s
Positive test 134 2733 599
Other 5974 3118 672

Formulate appropriate null and alternative hypotheses.
(M1 - the mean birth weight of babies of woman who tested positive,<br>M2 - the mean birth weight of babies of woman who either tested negative or were not tested)

a. Ho: M1 is not equal to M2.
Ha: M1 is equal to M2.
b. Ho: M1 is equal to M2.
Ha: M1 is not equal to M2.
c. Ho: M1 is greater than M2.
Ha: M1 is equal to M2.
d. Ho: M1 is equal to M2.
Ha: M1 is less than M2.
e. Ho: M1 is less than M2.
Ha: M1 is equal to M2.
Answer:
(d) Ho: M1 is equal to M2.
Ha: M1 is less than M2.

7. (Points: 2)
For the problem in question 6 find the value of the test statistic. Assume that the standard deviation for both populations is the same and use the pooled variance.

a. -6.57
b. -3.42
c. -1.45
d. 1.45
e. 3.42
f. 6.57
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Answer:

8. (Points: 2)
For the problem in question 6 find the P-value of the test.

a. -0.123
b. 0
c. 0.123
d. 0.367
e. 0.582
f. 1.34
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10. (Points: 1.5)
For the problem in question 6 give a left endpoint (lover limit, lower boundary) of the 95% confidence interval fo the mean difference (M1 - M2) in birth weights.
(M1 - the mean birth weight of babies of woman who tested positive,
M2 - the mean birth weight of babies of woman who either tested negative or were not tested)

a. - 543.15
b. -488.79
c. -385.67
d. -281.21
e. -126.41
f. 126.41
g. 281.21
h. 385.67
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11. (Points: 1.5)
For the problem in question 6 give a right endpoint (upper limit, upper boundary) of the 95% confidence interval for the mean difference (M1 - M2) in birth weights.
(M1 - the mean birth weight of babies of woman who tested positive,
M2 - the mean birth weight of babies of woman who either tested negative or were not tested)

a. - 543.15
b. -488.79
c. -385.67
d. -281.21
e. -126.41
f. 126.41
g. 281.21
h. 385.67