Question

An ANOVA F test is an extension of a

Question 1 options:

	two-sample z test.
	two-sample t test.
	two-sample test of proportions.
	a factorial ANOVA.

Question 2 (2 points)

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A manufacturer of infant formula is running an experiment using the standard (control) formulation and two new formulations, A and B. The goal is to boost the immune system in young children. There are 120 children in the study, and they are randomly assigned, 40 to each of the three feeding groups. The study is run for twelve weeks. The variable measured is Total IGA in mg per dl. It is measured at the end of the study, with higher values being more desirable. We are going to run a one-way ANOVA on these data. The hypotheses tested by the one-way ANOVA F test are

Question 2 options:

	Ho: The mean IGA score is the same for all three formulas. Ha: The mean IGA score is higher for both treatment groups than the control.
	Ho: The mean IGA score is the same for all three formula. Ha: The mean IGA score is not the same for at least one of the three formulas.
	Ho: The mean IGA score is the same for all three formulas. Ha: the mean IGA score is higher for at least one of the two treatment groups than the control.
	Ho: The mean IGA score is the same for all three formulas. Ha: the mean IGA score is lower for at least one of the two treatment groups than the control.

Question 3 (2 points)

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At what age do babies learn to crawl? Does it take longer to learn in the winter when babies are often bundled in clothes that restrict their movement? Data were collected from parents who brought their babies into the University of Denver Infant Study Center to participate in one of a number of experiments between 1988 and 1991. Parents reported the age (in weeks) at which their child was first able to creep or crawl a distance of four feet within one minute. The resulting data were grouped by month of birth. The data are for January, May, and September.

Birth Month	Average Crawling Age	SD	n
January	29.84	7.08	32
May	28.58	8.07	27
September	33.83	6.93	38

Crawling age is given in weeks. Assume that data are three independent SRSs, one from each of the three populations (babies born in a particular month), and that the populations of crawling ages have Normal distributions. The overall mean response is:

Question 3 options:

	7.30
	31.05
	30.75
	3.70

Question 4 (2 points)

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I have three groups for which I want to perform an ANOVA. They have standard deviations s1 = 2.5, s2 = 3.4, s3 = 6.4 and the plots of the data indicate all samples are approximately Normal with no outliers. Is the ANOVA appropriate?

Question 4 options:

	There is not enough information to tell.
	Yes
	There is too much information.
	No

Question 5 (2 points)

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A researcher is studying treatments for agoraphobia with panic disorder. The treatments are to be the drug Imipramine at the two doses 1.5 mg per kg of body weight and 2.5 mg per kg of body weight. There will also be a control group given a placebo. Thirty patients were randomly divided into three groups of ten each. One group was assigned to the control, and the other two groups were assigned to the two drug treatments. After twenty-four weeks on treatment, each of the subject's symptoms were evaluated through a battery of psychological tests, where high scores indicate a lessening of symptoms. Assume the data for the three groups are independent and approximately Normal with the same variance. An ANOVA F test tested the null hypothesis that there were no differences among the means for the three treatments that had a P-value less than 0.001. Which conclusion is correct?

Question 5 options:

	No choice is correct.
	There is strong evidence that the population mean scores for the higher dose group of 2.5 must be larger than the population mean for the lower dose group of 1.5.
	There is little evidence that the three population mean scores must all be different from each other because the P-value is so small.
	There is strong evidence that the three population mean scores must all be different from each other because the P-value is so small.

Answer 1