Question

Iron-deficiency anemia is the most common form of malnutrition in developing countries, affecting about 50% of children and women and 25% of men. Iron pots for cooking foods had traditionally been used in many of these countries, but they have been largely replaced by aluminum pots, which are cheaper and lighter. Some research has suggested that food cooked in iron pots will contain more iron than food cooked in other types of pots. One study designed to investigate this issue compared the iron content of some Ethiopian foods cooked in aluminum, clay, and iron pots. One of the foods was yesiga wet, beef cut into small pieces and prepared with several Ethiopian spices. The iron content of four samples of yesiga wet cooked in each of the three types of pots is given below. The units are milligrams of iron per 100 grams of cooked food.

obs     typepot g       iron
1       Alumin. 1       2
2       Alumin. 1       1.65
3       Alumin. 1       2
4       Alumin. 1       1.95
5       Clay    2       2.39
6       Clay    2       1.05
7       Clay    2       1.64
8       Clay    2       2.21
9       Iron    3       6.59
10      Iron    3       3.68
11      Iron    3       5.52
12      Iron    3       4.49

Make a table giving the sample size, mean, and standard deviation for each type of pot. Is it reasonable to pool the variances?

b) Run the analysis of variance. Report the F statistic with its degrees of freedom and P-value. What do you conclude? Round your test statistic to two decimal places. Round your P-value to three decimal places
F =  
P =  

Answer 1

(a)

Groups	Count	Sum	mean	standard deviation
Alumin	4	7.6	1.9	0.1683
Clay	4	7.29	1.8225	0.6062
Iron	4	20.28	5.07	1.2625

(b)F=20.71 and P=0.000

Anova: Single Factor
SUMMARY
Groups	Count	Sum	mean	standard deviation	Variance
Alumin	4	7.6	1.9	0.1683	0.028333
Clay	4	7.29	1.8225	0.6062	0.367425
Iron	4	20.28	5.07	1.2625	1.5938
ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Between Groups	27.46822	2	13.73411	20.70928	0.000429	4.256495
Within Groups	5.968675	9	0.663186
Total	33.43689	11