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237 questions match · page 8 of 10

CSIR NET June 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#the-shifted-up-sample-is-the-x-one-so-large-mu-drags-the-y-ranks-down

Let (X1,X2,…,X7)(X_{1}, X_{2}, \dots, X_{7}) and (Y1,Y2,…,Y9)(Y_{1}, Y_{2}, \dots, Y_{9}) be two independent random samples from the continuous distribution functions F(x−μ)F(x - \mu) and F(x−θ)F(x - \theta), respectively, where F,μF, \mu and θ\theta are all unknown. Further, let μ\mu be the unique median of F(x−μ)F(x - \mu) and θ\theta be the unique median of F(x−θ)F(x - \theta). Let RiR_{i} be the rank of YiY_{i} in the combined sample, i = 1, 2, …, 9. For testing H0:μ=θH_{0} : \mu = \theta against H1:μ>θH_{1} : \mu > \theta, the test statistic T=∑iT = \sum_{i}₌19Ri_{1}^{9} R_{i} is proposed. Then, which of the following statements are true?

Multi-select · full marks only for the exact set · Hypothesis Testing

CSIR NET June 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#balanced-and-orthogonal-are-different-properties-and-a-bibd-has-only-t

If the incidence matrix of a block design is given by N with rows (1, 1, 1, 0), (1, 1, 0, 1), (1, 0, 1, 1) and (0, 1, 1, 1), then which of the following statements are true?

Multi-select · full marks only for the exact set · Sampling and Design of Experiments

CSIR NET December 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#the-critical-value-sits-at-1-342-not-a-round-number-1-3-is-just-under

Let X1,X2,…,X15X_{1}, X_{2}, \dots, X_{15} be a random sample from an Exponential distribution with the probability density function f(x∣σ)=(1/σ)exp⁡(−x/σ)\sigma) = (1/\sigma)\exp(-x/\sigma) if x>0, 0 elsewhere, where the unknown parameter σ\sigma is positive. Let Xˉ=(1/15)∑115Xi{\bar{X}} = (1/15)\sum_{1}^{15}X_{i}. Suppose that φ\varphi denotes the likelihood ratio test for testing H0:σ≤1H_{0}: \sigma\le1 against H1:σ>1H_{1}: \sigma>1 at level α=0.1\alpha=0.1. It is given that χ152,0.1=22.307,χ152,0.9=8.547,χ302,0.1=40.256,χ302,0.9=20.599\chi^{2}_{15},_{0}._{1}=22.307, \chi^{2}_{15},_{0}._{9}=8.547, \chi^{2}_{30},_{0}._{1}=40.256, \chi^{2}_{30},_{0}._{9}=20.599, where P(W>χn2,a)=αP(W>\chi^{2}_{n},_{a})=\alpha and W~χn2\chi^{2}_{n}. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Hypothesis Testing

CSIR NET December 2025 · Part C (4.75 Marks)Complex Analysis, Algebra & Topology#eisenstein-only-blesses-the-cubic-the-other-two-quadratics-factor-by-i

Which of the following statements are true?

Multi-select · full marks only for the exact set · Rings and Fields

CSIR NET December 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#check-what-each-piece-actually-converges-to-before-trusting-the-ratio

Let X1,X2,…,Xn(n≥2)X_{1}, X_{2}, \dots, X_{n} (n\ge2) be a random sample from an Exponential distribution with the probability density function f(x∣μ,σ)=(1/σ)exp⁡((μ−x)/σ)\mu,\sigma) = (1/\sigma)\exp((\mu-x)/\sigma) if x>μ,0x>\mu, 0 otherwise, where parameters μ\mu and σ\sigma are unknown and positive. Let Xˉn,Sn2{\bar{X}}_{n}, S_{n}^{2} and X1:nX_{1}:_{n} denote the sample mean, the sample variance and the sample smallest order statistic, respectively, and let θ=σ/μ\theta = \sigma/\mu. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Estimation

CSIR NET December 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#check-each-statistic-against-the-symmetric-construction-directly-all-f

Consider a dataset of n observations given by A = {x1,x2,…,xnx_{1},x_{2},\dots,x_{n}}. Create a new dataset, given by B = {x1,x2,…,xn,−x1,−x2,…,−xnx_{1},x_{2},\dots,x_{n},-x_{1},-x_{2},\dots,-x_{n}}. Which of the following statements are always true? (Variance is calculated with divisor as the number of observations in the corresponding dataset.)

Multi-select · full marks only for the exact set · Sampling and Design of Experiments

CSIR NET December 2025 · Part C (4.75 Marks)Complex Analysis, Algebra & Topology#there-are-only-five-groups-of-order-8-check-which-ones-actually-have-n

Let G be a group of order 8. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · Groups

CSIR NET December 2025 · Part C (4.75 Marks)Analysis & Linear Algebra#a-terminating-decimal-is-approached-from-below-by-borrowing-one-digit

Let α=∑l=12025\alpha = \sum_{l=1}^{2025} al/10a_{l}/10ˡ with al∈a_{l} \in {0,1,…,9} for all 1≤l≤2025 and a2025≠0a_{2025}\ne0. Let (βn)n≥1(\beta_{n})_{n}\ge1 be a strictly increasing sequence of positive real numbers in (0,1) that converges to α\alpha. For each n≥1, write βn=∑l=1∞\beta_{n} = \sum_{l=1}^\infty bn,l/10b_{n,l}/10ˡ with bn,lb_{n,l}∈{0,1,…,9}, for the infinite decimal expansion of βn\beta_{n}. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · The Real Line

CSIR NET December 2025 · Part C (4.75 Marks)Analysis & Linear Algebra#f-maps-into-0-infinity-not-all-of-r-so-the-running-integral-is-always

Let F be the set of all functions f:[0,∞)→[0,∞)f : [0,\infty) \to [0,\infty) that are Riemann integrable on [0,t] for all t∈[0,∞)t\in[0,\infty). Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · Integration

CSIR NET December 2025 · Part C (4.75 Marks)ODE, PDE & Applied Mathematics#sin-of-1-over-x-is-approximately-1-over-x-for-large-x-so-r-grows-like

Consider the ordinary differential equation (ODE) y″ + r(x)y = 0, where r(x)=x3sin⁡(1/x)r(x) = x^{3}\sin(1/x) for x≠0, and r(0)=0. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Ordinary Differential Equations

CSIR NET December 2025 · Part C (4.75 Marks)Complex Analysis, Algebra & Topology#compact-hausdorff-and-connected-survive-any-product-size-metrizable-ne

Consider X=∏c∈(0,∞)X = \prod_{c\in(0,\infty)} [0,c] together with the product topology, where [0,c] is equipped with the euclidean topology. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · Topology

CSIR NET December 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#both-support-constraints-are-lower-bounds-on-theta-so-the-mle-is-their

Let X1,X2,…,Xn(n≥2)X_{1}, X_{2}, \dots, X_{n} (n\ge2) be a random sample from Uniform[−3θ/2,θ/2][-3\theta/2, \theta/2] distribution, where θ>0\theta>0 is an unknown parameter. Let Xˉ,X(1){\bar{X}}, X_{(1)} and X(n)X_{(n)} denote respectively the mean, the smallest order statistic and the largest order statistic of the sample. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Estimation

CSIR NET December 2025 · Part C (4.75 Marks)Complex Analysis, Algebra & Topology#the-cofinite-topology-is-coarser-than-euclidean-yet-not-regular-any-tw

Let τE\tau_E denote the euclidean topology on R\mathbb{R}. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · Topology

CSIR NET December 2025 · Part C (4.75 Marks)ODE, PDE & Applied Mathematics#a-constant-kernel-has-a-constant-resolvent-it-cannot-take-different-va

Let y(x) be the solution of the integral equation (IE) y(x) = eˣ +e+1+(1/3)∫01y(t)+ e + 1 + (1/3)\int_{0}^{1}y(t)dt, and R(x,t,1/3) be the resolvent kernel associated to IE. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Linear Integral Equations

CSIR NET December 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#with-alpha-and-beta-unspecified-the-prior-mean-is-a-free-parameter-no

Suppose X∣θ\theta ~ Binomial(7,θ),0<θ<1(7,\theta), 0<\theta<1, and the prior distribution of θ\theta is Beta(α,β)(\alpha,\beta) where α>0\alpha>0 and β>0\beta>0 are known. Then which of the following statements MAY NOT be true?

Multi-select · full marks only for the exact set · Probability

CSIR NET December 2025 · Part C (4.75 Marks)Analysis & Linear Algebra#the-anticommuting-space-allows-b21-to-be-nilpotent-which-is-never-diag

Let A∈M4(C)A \in M_{4}(\mathbb{C}) be such that A2=IA^{2} = I and Trace(A) = 0. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · Eigenvalues and Canonical Forms

CSIR NET December 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#with-2-servers-the-death-rate-caps-at-2-mu-once-both-servers-are-busy

Consider an M/M/2 queuing system with the birth rate λ=4\lambda=4 per minute, the death rate μ=1\mu=1 per minute, and the total capacity of 3 customers (including the ones that are being served). Let p0p_{0} and p3p_{3} denote the long-run probabilities that the system will be empty (i.e. without customers) and will be blocked (i.e. full), respectively. Which of the following statements are true?

Multi-select · full marks only for the exact set · Limit Theorems and Markov Chains

CSIR NET December 2025 · Part C (4.75 Marks)Analysis & Linear Algebra#rank-0-means-only-the-zero-matrix-so-that-orthogonality-condition-is-v

For n≥3, consider the space Mn(C)M_{n}(\mathbb{C}) of n×n complex matrices endowed with the inner product ⟨A,B⟩ = Trace(A*B). For 0≤k≤n, let Wk=W_{k} = {A∈Mn(C)A \in M_{n}(\mathbb{C}) : ⟨A,B⟩=0 for all B∈Mn(C)B \in M_{n}(\mathbb{C}) with rank k}. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · Inner Product Spaces and Forms

CSIR NET December 2025 · Part C (4.75 Marks)#31-days-beats-30-possible-borrower-lender-pairs-by-exactly-one-thats-t

There are six persons. On each day of the year 2024 at least one of them borrowed money from another. A person P is labeled troublesome in a calendar month M of 2024 if P borrowed from the same person at least twice during month M. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set

CSIR NET December 2025 · Part C (4.75 Marks)Analysis & Linear Algebra#substitute-the-relation-into-a-general-linear-combination-and-let-inde

Let V be a real vector space. Suppose that {u,v,w,x,y} ⊆ V is a spanning set of V and that {u,v,x,y} is linearly independent. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · Vector Spaces and Linear Maps

CSIR NET December 2025 · Part C (4.75 Marks)ODE, PDE & Applied Mathematics#the-isoperimetric-constraint-alone-pins-down-which-power-of-x-is-the-e

Suppose y(x) is the extremal of the variational problem J(y)=∫01x2(y′)2J(y) = \int_{0}^{1} x^{2}(y')^{2} dx subject to y(0)=0,y(1)=1,∫01y2y(0)=0, y(1)=1, \int_{0}^{1}y^{2}dx = 1/7. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Calculus of Variations

CSIR NET December 2025 · Part C (4.75 Marks)Probability, Statistics & Linear Programming#scaling-a-wishart-matrix-by-c-scales-sigma-by-c-not-by-1-over-c

Let X1,X2,…,X20X_{1}, X_{2}, \dots, X_{20} be a random sample from N12(μ,∑)N_{12}(\mu,\sum), where μ∈R12\mu\in\mathbb{R}^{12} and ∑\sum is positive definite. Suppose Xˉ=(1/20)∑i{\bar{X}} = (1/20)\sum_{i}₌120Xi_{1}^{20}X_{i} and S=(1/19)∑iS = (1/19)\sum_{i}₌120(Xi−Xˉ)(Xi−Xˉ)T_{1}^{20}(X_{i}-{\bar{X}})(X_{i}-{\bar{X}})^{T}. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Linear Models and Multivariate

CSIR NET December 2025 · Part C (4.75 Marks)ODE, PDE & Applied Mathematics#differentiate-e-and-substitute-the-pde-the-boundary-term-vanishes-beca

Let u(x,t) be the solution of the initial-boundary value problem utt−uxx+ut=0,0<x<π,t>0,u(0,t)=0,u(π,t)=0,t>0,u(x,0)=sin⁡x,ut(x,0)=0,0<x<πu_{tt} - u_{xx} + u_{t} = 0, 0<x<\pi, t>0, u(0,t)=0, u(\pi,t)=0, t>0, u(x,0)=\sin x, u_{t}(x,0)=0, 0<x<\pi. For t≥0, define E(t)=∫0π(ut2+ux2)E(t) = \int_{0}^\pi (u_{t}^{2}+u_{x}^{2}) dx. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Partial Differential Equations

CSIR NET December 2025 · Part C (4.75 Marks)ODE, PDE & Applied Mathematics#gauss-seidel-for-a-2x2-system-converges-exactly-when-the-off-diagonal

Let S be the set of all 2×2 matrices A such that the iterative sequence generated by the Gauss-Seidel method converges for every initial guess, when employed to solve the system of equations A(x1,x2)T=(1,2)TA(x_{1},x_{2})^{T}=(1,2)^{T}. Then which of the following statements are true?

Multi-select · full marks only for the exact set · Numerical Analysis

CSIR NET December 2025 · Part C (4.75 Marks)Complex Analysis, Algebra & Topology#z-mod-9-satisfies-the-chain-condition-and-still-has-zero-divisors

Consider a commutative ring R with unity with at least five elements such that for any two elements a,b∈R, there exists c∈R such that a=bc or b=ac. Which of the following statements are necessarily true?

Multi-select · full marks only for the exact set · Rings and Fields

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