Probability Engine · STA210

Statistics II (BSc CSIT, STA210): the questions likely to come

32 analyzed questions from 8 past papers (2074-2082), grouped by syllabus unit — each with its probability, how often it's been asked, and where to study the answer.

8
Papers analyzed
2074-2082
32
Analyzed questions
across 6 syllabus units
4
Very likely units
high-probability topics
4
Units = 80% of marks
study these first
Model answers for this subject are being written. Every question links to its original paper so you can study from the source meanwhile.
Pick a unit
U1 · Q1/8 · 207910 marks
Probability and Probability Distributions

Define a probability distribution. Explain the binomial distribution with its mean and variance, and state the conditions under which it is applied.

32%
Possible to appearAppeared in 3 of the last 3 board papers
Seen in
How well do you know this?rating moves you on
MODEL ANSWERU1 · 10 marks

Probability Distribution

A probability distribution is a mathematical function (or table) that assigns to each possible value of a random variable the probability of its occurrence. For a discrete random variable XX taking values x1,x2,x_1, x_2, \dots it is described by the probability mass function P(X=xi)=piP(X = x_i) = p_i with pi0p_i \ge 0 and ipi=1\sum_i p_i = 1; for a continuous variable it is described by a probability density function f(x)f(x) with f(x)0f(x) \ge 0 and f(x)dx=1\int_{-\infty}^{\infty} f(x)\,dx = 1.

Binomial Distribution

A discrete random variable XX follows a binomial distribution if it counts the number of successes in nn independent Bernoulli trials, each having success probability pp (and failure q=1pq = 1 - p). Its probability mass function is

P(X=x)=(nx)pxqnx,x=0,1,2,,n.P(X = x) = \binom{n}{x} p^{x} q^{\,n-x}, \qquad x = 0, 1, 2, \dots, n.

Mean and Variance

Mean μ=E(X)=np,Variance σ2=npq.\text{Mean } \mu = E(X) = np, \qquad \text{Variance } \sigma^{2} = npq.

Since q<1q < 1, the variance npqnpq is always less than the mean npnp, i.e. for the binomial distribution mean >> variance.

Outline of the mean: writing X=i=1nXiX = \sum_{i=1}^{n} X_i where each XiX_i is Bernoulli with E(Xi)=pE(X_i)=p, by linearity E(X)=E(Xi)=npE(X)=\sum E(X_i)=np; similarly Var(Xi)=pq\operatorname{Var}(X_i)=pq and by independence Var(X)=npq\operatorname{Var}(X)=npq.

Conditions for Application

The binomial distribution applies when:

  1. The number of trials nn is fixed and finite.
  2. Each trial has only two outcomes — success or failure (dichotomous).
  3. The trials are independent of one another.
  4. The probability of success pp remains constant from trial to trial.

Examples: number of heads in 10 tosses of a coin, number of defective items in a sample of fixed size, number of correct answers in a multiple-choice test.

AI-generated answer · unverifiedView in 2079 paper →
U1 · Question 1 of 8
Question Priority · U1ranked by appearance likelihood — study top-down

Probability and Probability Distributions

Analyzed next54%
1
★ TOP PICK

Define a probability distribution. Explain the binomial distribution with its mean and variance, and state the conditions under which it is applied.

10 marksSEEN IN
32%
2

Define index numbers and explain Laspeyres' and Paasche's price index methods.

5 marksSEEN IN
54%
3

State and explain the addition and multiplication theorems of probability with examples.

5 marksSEEN IN
52%
4

Explain the Poisson distribution with its mean and variance and state its applications.

5 marksSEEN IN
52%
5

Define a random variable. Differentiate between discrete and continuous random variables with examples.

5 marksSEEN IN
52%
6

Explain the normal distribution and its properties. The mean of a normal distribution is 50 and standard deviation is 10; find the probability that a value lies between 45 and 62.

10 marksSEEN IN
24%
7

Define mathematical expectation. State and prove its properties.

5 marksSEEN IN
48%
8

Define stochastic process. In a town each day is either sunny or rainy. A sunny day is followed by another sunny day with probability 0.8, whereas a rainy is followed by sunny day is with probability 0.4. If it rains on Sunday, make forecast for Monday and Tuesday.

5 marksSEEN IN
25%
03The mock

Sit a probable paper

A full mock exam built from the most likely questions, mirroring the real paper's structure. Every slot is a real past question.

Most Probable Paper

Mirrors the real structure · 60 marks · based on 8 past papers

Section A: Long Answer QuestionsAttempt any TWO questions.
  1. 1.

    What is hypothesis testing? Explain the procedure of testing of hypothesis including null and alternative hypotheses, level of significance, types of errors and the critical region.

    [10 marks]
    Testing of HypothesisVery likelyfrom 2080 paper →

    This question has recurred in 4 of 8 years; so far only in internal assessments, not the board; and its topic (Testing of Hypothesis) appears in 100% of years.

  2. 2.

    What is sampling? Explain different methods of probability and non-probability sampling with their merits and demerits.

    [10 marks]
    Sampling and Sampling DistributionsVery likelyfrom 2081 paper →

    This question has recurred in 4 of 8 years; so far only in internal assessments, not the board; and its topic (Sampling and Sampling Distributions) appears in 88% of years.

  3. 3.

    Define a probability distribution. Explain the binomial distribution with its mean and variance, and state the conditions under which it is applied.

    [10 marks]
    Probability and Probability DistributionsVery likelyfrom 2079 paper →

    This question has recurred in 3 of 8 years; so far only in internal assessments, not the board; and its topic (Probability and Probability Distributions) appears in 100% of years.

Section B: Short Answer QuestionsAttempt any EIGHT questions.
  1. 1.

    Define Karl Pearson's coefficient of correlation and state its properties.

    [5 marks]
    Correlation and RegressionVery likelyfrom 2081 paper →

    This question has recurred in 6 of 8 years; so far only in internal assessments, not the board; and its topic (Correlation and Regression) appears in 88% of years.

  2. 2.

    What are regression coefficients? State their properties.

    [5 marks]
    Correlation and RegressionVery likelyfrom 2081 paper →

    This question has recurred in 6 of 8 years; so far only in internal assessments, not the board; and its topic (Correlation and Regression) appears in 88% of years.

  3. 3.

    Explain the concept of sampling distribution and standard error.

    [5 marks]
    Sampling and Sampling DistributionsVery likelyfrom 2081 paper →

    This question has recurred in 6 of 8 years; so far only in internal assessments, not the board; and its topic (Sampling and Sampling Distributions) appears in 88% of years.

  4. 4.

    Define index numbers and explain Laspeyres' and Paasche's price index methods.

    [5 marks]
    Probability and Probability DistributionsVery likelyfrom 2081 paper →

    This question has recurred in 5 of 8 years; so far only in internal assessments, not the board; and its topic (Probability and Probability Distributions) appears in 100% of years.

  5. 5.

    State and explain the addition and multiplication theorems of probability with examples.

    [5 marks]
    Probability and Probability DistributionsVery likelyfrom 2081 paper →

    This question has recurred in 5 of 8 years; so far only in internal assessments, not the board; and its topic (Probability and Probability Distributions) appears in 100% of years.

  6. 6.

    Explain the Poisson distribution with its mean and variance and state its applications.

    [5 marks]
    Probability and Probability DistributionsVery likelyfrom 2081 paper →

    This question has recurred in 5 of 8 years; so far only in internal assessments, not the board; and its topic (Probability and Probability Distributions) appears in 100% of years.

  7. 7.

    Define a random variable. Differentiate between discrete and continuous random variables with examples.

    [5 marks]
    Probability and Probability DistributionsVery likelyfrom 2081 paper →

    This question has recurred in 5 of 8 years; so far only in internal assessments, not the board; and its topic (Probability and Probability Distributions) appears in 100% of years.

  8. 8.

    Define mathematical expectation. State and prove its properties.

    [5 marks]
    Probability and Probability DistributionsVery likelyfrom 2080 paper →

    This question has recurred in 5 of 8 years; so far only in internal assessments, not the board; and its topic (Probability and Probability Distributions) appears in 100% of years.

  9. 9.

    Explain the F-test for the equality of two population variances.

    [5 marks]
    Testing of HypothesisVery likelyfrom 2081 paper →

    This question has recurred in 5 of 8 years; so far only in internal assessments, not the board; and its topic (Testing of Hypothesis) appears in 100% of years.

04The receipts

Behind the numbers

The raw evidence the predictions are computed from: marks per unit per year, syllabus weights, trends, and coverage.

Show the heatmap, topic table and coverage analysis

The receipt: marks per unit, per year

Each row is a syllabus unit, each column an exam year, each cell the marks that unit earned that year. Click any cell to see the actual questions behind it.

Marks:nonefew → many
2074
2075
2077
2078
2079
2080
2081
2082
Total
U1Probability and Probability Distributions
180
U4Testing of Hypothesis
180
U5Correlation and Regression
90
U2Sampling and Sampling Distributions
80
U3Estimation
60
U6Non-Parametric Tests and Statistical Quality Control
10
#Syllabus unitProbabilityAppearedAvg marksSyllabus weightExam vs syllabusTrendQuestions
1U1Probability and Probability DistributionsVery likely100%22.522%10 lecture hrsOver-examinedexam 30% · syllabus 22%Fading7 recurring8 total
2U4Testing of HypothesisVery likely100%22.527%12 lecture hrsBalancedexam 30% · syllabus 27%Steady5 recurring12 total
3U5Correlation and RegressionVery likely88%12.911%5 lecture hrsBalancedexam 15% · syllabus 11%Steady3 recurring4 total
4U2Sampling and Sampling DistributionsVery likely88%11.418%8 lecture hrsBalancedexam 13% · syllabus 18%Steady2 recurring4 total
5U3EstimationLikely75%1016%7 lecture hrsUnder-examinedexam 10% · syllabus 16%Steady2 recurring3 total
6U6Non-Parametric Tests and Statistical Quality ControlOccasional12%107%3 lecture hrsBalancedexam 2% · syllabus 7%Risingnone repeat1 total

Study smart, not hard

Drag the slider: studying the top 4 units in priority order covers ~88% of all observed marks.

  1. ~80% line

Lecture time vs exam marks

Where the exam pays more than the curriculum spends: ● lectures vs ● exam marks, as a share of the whole course. A long teal-leading bar = high-yield unit.

U1Probability and Probability Distributions
22% of lectures → 30% of markshigh yield
U4Testing of Hypothesis
27% of lectures → 30% of marks
U5Correlation and Regression
11% of lectures → 15% of marks
U2Sampling and Sampling Distributions
18% of lectures → 13% of marks
U3Estimation
16% of lectures → 10% of markslow yield
U6Non-Parametric Tests and Statistical Quality Control
7% of lectures → 2% of marks

Topics are the official STA210 syllabus units. Predictions are data-driven probabilities computed from 8 past papers (2074-2082) by mapping each real question to its syllabus unit. They indicate what has historically been likely, not guaranteed questions. Always study the full syllabus.