Question

3. To determine the nature and extent to which neurobehavioral changes occur in association with the
toxicity resulting from exposure to excess dietary iron (Fe), Sobotka et al. 2015 used weanling Sprague-
Dawley rats as experimental subjects. The researchers assigned the animals to one of five diets
differentiated on the basis of the amount of Fe present: 4 ppm, 35 ppm, 350 ppm, 3500 ppm, and
10,000 ppm. Two randomly selected rats were obtained from each of three laboratories (selected at
random from a total of 6 available labs) and were assigned to each of the 5 diets. The data (body weight
in grams after 10 weeks) are given below. Analyze the data as a 2-level nested ANOVA. Put your
hypotheses and your conclusions in the box provided using our standard format. The correct ANOVA
table should be put out to the right. Think about which factor is the top level in this analysis.
		Iron (Fe) in Diet
	4 ppm	35 ppm	350 ppm	3500 ppm	10,000 ppm
Laboratory 1	292	396	368	319	216
	291	335	349	302	218
Laboratory 2	281	331	325	331	254
	220	349	300	285	218
Laboratory 3	237	377	364	392	231
	242	373	366	369	220

Put your answers in column B using the standard format
Hypotheses:	Ho
	Ha:
	Ho:
	Ha:

Conclusions:

Answer 1

Hypothesis:

H₀: µ₁ = µ₂ = µ₃ = µ₄ = µ₅

H₁: At least one means is not equal

The SPSS output is:

Univariate Analysis of Variance Between-Subjects Factors PPM Laboratory 1 10 Sig. .000 .000 Tests of Between-Subjects Effects Dependent Variable: Samples Type III Sum Source of Squares Mean Square F Corrected Model 96622.4679 6901.605 15.742 Intercept 2791360.033 1 2791360.033 6366.669 PPM 81894.467 20473.617 46.697 Laboratory 4027.267 2013.633 4.593 PPM * Laboratory 10700.733 1337.592 3.051 Error 6576.500 438.433 Total 2894559.000 30 Corrected Total 103198.967 a. R Squared= .936 (Adjusted R Squared= .877) .000 .028 .030

The p-value for interaction is 0.030.

Since the p-value (0.030) is less than the significance level, we can reject the null hypothesis.

Therefore, we can conclude that neurobehavioral changes occur in association with the toxicity resulting from exposure to excess dietary iron (Fe).

Please give me a thumbs-up if this helps you out. Thank you!