Fiftieth Percentile Research Articles

GROWTH AND DEVELOPMENT OF PERUVIAN CHILDREN

One hundred nine school children from 2 rural areas in the coastal area of Peru were measured and weighed and roentgenograms of the hand and wrist were obtained. Three-fourths of the children were below Stuart's tenth percentile in height. Roughly, a third of the children were below the tenth percentile in weight. Fifteen per cent of the girls and 30 per cent of the boys were above the fiftieth percentile in weight. Forty to forty-five per cent of the children were in the stocky to obese channels of the Wetzel grid; 5 to 10 per cent would be classified as fair to poor, and roughly half would be considered average. Developmental age (Wetzel) was 7.5 ± 15.6 months less than chronological age for boys, 10.5 ± 11.3 months less for girls. A third of the boys and 15 per cent of the girls were advanced in Wetzel developmental age. It was apparent that the heavier children were generally advanced in Wetzel developmental age. Roentgenograms of the hand and wrist were assessed by comparing the films to the Greulich-Pyle Standards. Skeletal age was -11.3 ± 12.7 months for boys and -7.1 ± 9.8 for girls. Eighteen per cent of the population were advanced in skeletal age. Boys were more retarded than girls in skeletal age. The correlation and partial correlation coefficients for all combinations of the 4 measurements (retardation in weight, retardation in height, retardation in skeletal age and retardation in developmental age) were calculated. The various pairs were all rather highly correlated, this being particularly true of weight and Wetzel developmental age. The partial correlation coefficients show, however, that skeletal age was not closely correlated with any of the other 3 measurements. Height and developmental age were negatively correlated to a significant degree, and developmental age and weight were so closely related that they appear to be measures of the same characteristic in this population. Individual dietary histories are not available from these children, but it is known that the diets in the area are considerably below recommended levels in certain nutriients. Whether dietary deficiencies are factors in the apparently abnormal developmental patterns, or if the patterns are truly abnormal for the Peruvian child or indicate an adverse effect on health, remain to be shown. It is pointed out that there are probably advantages in studies upon growth and development in different areas of the world where a variety of dietary or environmental factors may have specific effects.

An Experiment in Guidance

OR some years past the music department of the Medina County (Ohio) Schools has administered musical talent tests to pupils in the fifth and sixth grades in an effort to discover what pupils should take advantage of the opportunities for music study offered in the school instrumental classes. During the last school year careful record was kept of enrollment both before and after the tests were given, so that an accurate report might be made regarding the effectiveness of such tests in stimulating interest in instrumental study and in bringing about increased enrollment in the classes. Enrollment for instrumental classes is taken during the first week of school. At that time the children who have already decided to study an instrument sign up for the classes. Last year the names of these students were kept separate from later registrants so that it would be possible to tell which pupils came into the classes entirely as a result of the tests. During the second week of school, four of the Kwalwasser-Dykema music tests were given in all the fifth and sixth grade rooms of the county, these being the grades from which most of the beginning instrumental pupils are recruited. The four tests given were the pitch discrimination, the tonal memory, the rhythmic imagery and the tonal imagery. The question may arise as to why only these four were used instead of the entire battery of tests. The reason was largely one of administrative necessity; to give and grade all of the tests would have required more time than was available. It seemed that the pitch discrimination and tonal memory tests would give a fairly good indication of the natural underlying musical sensitivity of the children, and that the rhythmic and tonal imagery tests would give some indication of how well the children had responded to the usual musical instruction in their regular classrooms. The assumption was that a child who is naturally musical will acquire more knowledge of music notation in the regular school classes than one who possesses more meagre musical talent. All of the papers were graded and the pupils were given percentile rankings according to the plan outlined in the manual of instructions accompanying the tests. If a child received a percentile ranking of fifty or above in any one of the tests it was assumed that he had average or more than average ability in the musical capacity measured by that particular test. Since four tests were given, it was assumed that a child who ranked above fifty in any three of them probably possessed more than the average amount of musical talent and would therefore make a good candidate for class instrumental instruction. To the parents of these children who ranked above the fiftieth percentile in three or more of the tests, the following letter was sent, by mail so that it might receive more careful consideration and attention.