BGCSE Statistics 4040 study guide
BGCSE Statistics 4040 · Work through your exam, one topic at a time.
The BGCSE Statistics 4040 is a secondary-school certificate examination in statistics, taken by candidates in The Bahamas as part of the Bahamas General Certificate of Secondary Education. It suits students completing senior secondary schooling who need a quantified subject for further study or employment, and mature candidates returning to study. The BGCSE Statistics 4040 study guide has 8 sections and about 2,905 words.
01Data Collection and Sources
Every statistical investigation begins with a question and a plan. Candidates should distinguish primary data (collected first-hand by the investigator, e.g.
393 words, about 2 min02Data Presentation and Display
Choosing an appropriate display depends on the type of data. For qualitative data use bar charts (gaps between bars) and pie charts (proportions of a whole).
347 words, about 2 min03Measures of Central Tendency and Dispersion
Know the three averages : mean (sum ÷ count), median (middle value of ordered data), and mode (most frequent value, or modal class for grouped data). Understand when each is best: the mean uses all values but is distorted by outliers ; the median resists outliers and suits skewed data; the mode suits categorical data and identifies the most common item.
356 words, about 2 min04Probability
Probability measures how likely an event is, on a scale from 0 (impossible) to 1 (certain). For equally likely outcomes, P(event) = number of favourable outcomes ÷ total outcomes.
324 words, about 2 min05Correlation and Regression
Correlation describes the strength and direction of a linear relationship between two variables. On a scatter diagram , look for positive (both increase), negative (one increases as the other falls) or no correlation.
388 words, about 2 min06Time Series and Index Numbers
A time series is data recorded at successive points in time. Its four components are the trend (long-term direction), seasonal variation (regular repeating pattern within a year), cyclical variation (longer, irregular waves) and random/irregular variation .
365 words, about 2 min07Sampling and Sampling Distributions
Know the main sampling methods : simple random sampling (every member of a numbered list equally likely, e.g. using random numbers), systematic sampling (every kth item from a list), stratified sampling (split the population into strata and sample proportionally), quota sampling (fixed numbers per group chosen by the interviewer), and cluster sampling (sample whole groups).
336 words, about 2 min08Statistical Inference and Interpretation
Inference means drawing conclusions about a population from sample data. Know how to construct and interpret a confidence interval for a mean: x̄ ± z × (σ ÷ √n), where z = 1.96 for 95% confidence and 1.645 for 90%.
396 words, about 2 min