Collecting data · Coleta de dados
| English | Português |
|---|---|
| population/ˌpɒpjʊˈleɪʃn/ | população |
| sample/ˈsæmpl/ | amostra |
| representative/ˌreprɪˈzentətɪv/ | representativa |
| qualitative data/ˈkwɒlɪteɪtɪv ˈdeɪtə/ | dados qualitativos |
| quantitative data/ˈkwɒntɪteɪtɪv ˈdeɪtə/ | dados quantitativos |
| discrete/dɪˈskriːt/ | discretos |
| continuous/kənˈtɪnjuːəs/ | contínua |
| histogram/ˈhɪstəɡræm/ | histograma |
Define whom a finding describes
- A population 总体 is the target group; a sample 样本 is the observed subset. A class survey can describe that class without establishing a school-wide percentage.
- A suitably representative 有代表性的 sample requires attention to selection, participation and the question asked. A large voluntary response does not automatically resolve nonresponse.
Distinguish labels from measured amounts
- Qualitative data 定性数据 are categories. Quantitative data 定量数据 measure amounts; discrete · discretos 离散 data use distinct countable values, while continuous 连续 data are modelled over intervals.
- A numerical route label is still a category. Recorded continuous measurements can be rounded, so printed decimal precision alone does not decide the underlying type.
Match each variable to its data type. · Combine cada variável com seu tipo de dado.
Counted values are discrete; measured values are continuous. The type decides which chart is legitimate. · Valores contados são discretos; valores medidos são contínuos. O tipo decide qual gráfico é legítimo.
Match the display to the data
- A histogram 直方图 uses numeric class intervals. For unequal widths, frequency density is frequency divided by width so bar area represents frequency.
- Separate category bars and label units, scale and count scope. A pie chart requires mutually exclusive parts of a defined whole; missing responses must not silently become a known category.
Which chart suits continuous data such as height? · Qual gráfico se adapta a dados contínuos como altura?
A histogram displays frequencies over numeric intervals. With unequal interval widths, use frequency density so area represents frequency; an empty interval can have zero height. · Um histograma mostra frequências sobre intervalos numéricos. Com larguras de intervalo desiguais, use densidade de frequência para que a área represente a frequência; um intervalo vazio pode ter altura zero.
Two sampling plans have different risks. Asking a canteen queue excludes nonusers. Selecting every tenth name can cover the full roll, but needs a random start and a check for patterns in the ordering. Neither method guarantees honest responses or removes all nonresponse; record the actual procedure and limits.
To study canteen preferences across a school, which listed selection plan best covers the full student population? · Para estudar preferências de cantina em toda uma escola, qual plano de seleção listado melhor cobre toda a população estudantil?
Selection from the full roll can include nonusers. A systematic every-tenth-name plan needs a random start and a check for patterns; nonresponse remains a limitation, so it does not guarantee perfect representativeness. · Seleção da lista completa pode incluir não usuários. Um plano sistemático a cada décimo nome precisa de início aleatório e verificação de padrões; não-resposta permanece limitação, logo não garante representatividade perfeita.
State the denominator. If 60 of 200 students reply and 45 prefer later meetings, response rate is 30% and respondent preference is 75%. Preferences of the remaining 140 are unknown. Sheet 2.5 separates preference evidence from attendance evidence.
A larger sample removes bias caused by how the sample was chosen. · Uma amostra maior remove o viés causado pela escolha da amostra.
Increasing sample size alone does not remove systematic selection or nonresponse bias. Examine and improve the collection method and disclose remaining limits. · Aumentar o tamanho da amostra sozinho não remove viés de seleção sistemática ou não-resposta. Examine e melhore o método de coleta e disclosure limites restantes.
A truncated category-bar axis changes the visible comparison of heights. Use a zero baseline for straightforward magnitude comparisons, and make any exceptional scale choice explicit. A larger sample does not by itself fix a systematically selected sample.
A bar chart's vertical axis starts at 40 rather than 0. What must you do? · O eixo vertical de um gráfico de barras começa em 40 em vez de 0. O que você deve fazer?
A truncated category-bar scale can exaggerate relative heights. A zero baseline supports magnitude comparisons; any exception needs a clear, justified scale rather than an unstated change. · Uma escala de barra de categoria truncada pode exagerar alturas relativas. Uma base zero suporta comparações de magnitude; qualquer exceção precisa de escala clara e justificada em vez de mudança não declarada.