Question

FOR QUESTIONS 83 TO 90 USE THE FOLLOWING DIRECTION: A researcher theorizes that first-born children of African-American families are more intelligent than other African-American children. A sample of 50 first-born children of African-American families is found to have an average IQ of 105, while based on other studies we can assume that IQ of other African-American children is 100 on average and has standard deviation of 15.

What is the population of interest in this study?

A. All African-American families
B. All African-American children
C. IQ of African-American children
D. IQ of all first-born African-American

Which method researcher can use to check her idea?
A. Hypothesis testing - Z test
B. Hypothesis testing - t test
C. Sample size estimation for average
D. None of the above

If she conducts hypothesis testing, she has to consider:
A. one-tailed test
B. two-tailed test
C. one-tailed test because sample size is large
D. two-tailed test because sample size is large

What would be the null hypothesis of this study?
A. H0: Mean= 50
B. H0: Mean = 105
C. H0: Mean = 15
D. H0: Mean > 105
E. None of the above

What would be the alternative hypothesis of this study?
A. Ha: Mean= 50
B. Ha: Mean = 105
C. Ha: Mean > 100
D. Ha: Mean > 105
E. None of the above

What level of significance do you choose for this test?
A. Level of significance = 50
B. Level of significance = 10
C. Level of significance = 95%
D. Level of significance = 99%
E. None of the above

What is the computed value of test statistic?
A. -2.4
B. -1.5
C. +1.5
D. +2.4

Which one of the following is a correct conclusion based on the data given? Use 5% significance level.
A. Reject H0. First-born children of African-American families are more intelligent than other children.
B. Do not reject H0. First-born children of African-American families are not more intelligent than other children.
C. Reject H0. First-born children of African-American families are not more intelligent than other children.
D. None of the above.

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Answer 1