170,595 research outputs found
Little statisticians grow up: Exploring the concept of variability in young children
No full textLITTLE STATISTICIANS GROW UP:
EXPLORING THE CONCEPT OF VARIA
BILITY IN YOUNG CHILDREN
Gianmarco Altoè
and Franca Agnoli
Università degli Studi di Padova, Padova, Italy
[email protected]
Variability is a central concept in statistic
al reasoning. Indeed, a major goal of most
introductory statistics courses is to help student
s understand and be aware of the omnipresence of
variability and the quantification and explanation of variability (Cobb, 1992). However, in
curriculum design and in statistics education r
esearch, variability has not been given enough
attention (Reading & Shaughnessy, 2004).
Despite the widespread belief in the importa
nce of this concept, only recently have
educational researchers devoted their attention to
the study of how reasoning about variability
develops (Garfield & Ben-Zvi, 2005). Current resear
ch on the concept of statistical variation has
mainly focused on high school and college students (e.g., del Mas & Liu, 2005). These studies
demonstrate that it is extremely difficult for students with statistical training – and even for their
teachers - to reason about variability. However, little
is known about the understanding of statistical
variability in young children.
The main aim of this study is to explore
intuitive ideas about variability in 4-6-year old
children using a quantity judgment task. Specifi
cally, we assessed whether children’s responses
were affected by increasing levels of stimulus va
riability. In addition, we investigated the role of
age and numerical skills in children’s performance.
Participants included 110 children (49%
boys) aged 4-6 years recruited in two
kindergartens and a primary school in Northern It
aly. Children were individually assessed using a
computerized task in which they were asked to co
mpare two sets of chocolate bars. In the first set,
the mean and standard deviation of the chocolate
bars were held constant; in the second set, both
were manipulated. A standardized test of
numerical ability was also administered.
The key findings were: 1) Children’s perform
ance was affected by stimulus variability
following a non-monotonic trend. Increasing levels of
variability were associated with a decrease in
correct responses, but very low levels of variability
(i.e., close to 0) were also unexpectedly related
to a decrease in response accuracy; 2) Children’
s performance significantly increased with age
following a linear trend; in addition, marked inte
r-individual differences were found; 3) Statistical
and numerical skills were only
moderately intercorrelated.
Overall, these results suggest that young child
ren have an intuitive idea of the concept of
variability. The reasoning processes underlying this
concept are complex and need to be further
investigated. The next steps will be to replicat
e this study among children and young adults to
analyze the characteristics of st
atistical reasoning about variability
across different age groups. In
our opinion, understanding how children’s concept
of variability develops is necessary to
implement efficient teaching strategies in multiple educational settings.
REFERENCES
Cobb, G. W. (1992). Report of the joint AS
A/MAA committee on undergraduate statistics.
In the
American Statistical Association 1992 proceedings
of the Section on Statistical Education
,
(pp. 281–283). Alexandria, VA: American Statistical Association.
delMas, R. C., & Liu, Y. (2005). Exploring stude
nts’ conceptions of the standard deviation.
Statistics Education Research Journal
,
4
(1), 55–82.
Garfield, J., & Ben-Zvi, D. (2005). A frame
work for teaching and assessing reasoning about
variability.
Statistics Education Research Journal, 4(1)
, 92–99.
Reading, C., & Shaughnessy, J. M. (2004). Reas
oning about variation. In D. Ben-Zvi & J.
Garfield (Eds.),
The challenge of developing statistical literacy, reasoning, and thinking
(pp. 201–
226). Dordrecht, The Netherlands: Kluwer Academic Publishers
Correlazione illusoria e stereotipo etnico in età evolutiva
No full textRecent studies have shown that the illusory correlation bias is present in children starting as early as age six. In the original experimental paradigm used with adults and subsequently adapted for children, the distinction between a majority and a minority group rests uniquely upon the numerical size of the two groups, so that the majority group is assigned the larger number of behaviors. In the present study we use, in addition to the numerical distinction of the two groups, a second distinction based on the ethnicity of the members of the groups. In this case the child observer may or may not be a member of the ethnic group presented. The results show that the illusory correlation bias disappears when the children observers (Italian children) are presented with situations in which members of their own ethnic group are the numerical minority. This is achieved by presenting a majority group that has somatic traits commonly associated with African children and a minority group with somatic traits of European children. These results emphasize how membership in a group can interfere with the formation of the illusory correlation bias intended solely as a cognitive error
Children correlate infrequent behaviors with minority groups: a case of illusory correlation
No full textEstrogen receptors alpha and beta expression in different canine cancer types with an emphasis on hematopoietic malignancies
No full textEstrogen receptors (ERs) are located in both healthy and neoplastic tissues. The type of estrogen receptor expressed varies depending on its location, tumor type, and species. Estrogen action is mediated by binding to ER and activating the transcriptional and signaling processes that result in the control of gene expression. There are two main types of estrogen receptors: ER alpha (ER alpha) and ER beta (ER beta). Both receptors are functionally different, they may act antagonistically and are distributed in different tissues but their structure is similar - as they are composed of 5 different domains: A/B, C, D, E, and F. The signaling pathway and hence regulation of the gene expression by ERs is a complex and multifactorial process that involves both genomic and nongenomic actions. In the human reproductive tract, both ER alpha and beta are present, with predominant expression of ER beta, while there are no satisfactory data distinguishing the type of ERs expressed in the canine reproductive tract. In mammary gland neoplasia, a decreased or lacking ER alpha expression in humans is associated with a poorer prognosis. This is similar to dogs, where higher ER alpha expression intensity was noted in benign tumors than in carcinomas. In human hematopoietic malignancies, ER beta is a predominant receptor. Selective and non-selective ER beta agonists have an antiproliferative and pro-apoptotic effect on human lymphoma cell lines and may be effective in the therapy of ER beta positive lymphomas and leukemias. In canine lymphoma tissues, none or only marginal expression of ERs was detected over the decades. Considering available data, we conducted preliminary studies proving that, in contrast to humans, the dominant ER expressed in canine hematopoietic tumors is ER alpha
On the thermal response of buildings under the synergic effect of heat waves and urban heat island
No full textGlobal and local climate change increases the occurrence and the magnitude of extreme phenomena, as urban heat island and heat waves. These phenomena seriously affect the quality of life in several aspects: society, health, environment; they also heavily affect the building sector, increasing the energy use for cooling and deteriorating the indoor thermal environment. This paper utilizes data from a continuous urban microclimatic monitoring over three years to quantify the impact of heat waves on the thermal quality of two reference residential buildings in the city of Rome, Italy. The synergic effect of heat waves with the urban heat island is also analysed. The observation period includes summers of 2015, 2016 and 2017. The buildings’ response is analysed through numerical thermal analyses in transient regime, taking into account several variants: thermal insulation, mechanical cooling system and thermal free-floating conditions, with different night ventilation strategies. Results show that daily average temperature and urban heat island intensity increase by up to 4.3 °C and 1.5 °C respectively during the heat waves with respect to the rest of the summer. The building cooling energy use rises up 87% during heat wave periods, while average operative temperature in free-running buildings increments by up to 3.5 °C. Results also show the impressive combined impact of heat wave and heat island: triplication of cooling energy use in the worst case and increase of the average operative temperature above 5 °C
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