Χ 2cdf(left bound, right bound, df) corresponds to P(left bound Χ 2.Χ 2pdf( x, df) yields the probability density function value, only useful to plot the chi 2 curve, in which case " x" is the variable.tcdf(left bound, right bound, df) corresponds to P(left bound t.tpdf( x, df) yields the probability density function value, only useful to plot the student- t curve, in which case " x" is the variable).invNorm( p) yields the critical value, k: P( Z k) = p for the standard normal.invNorm( p, μ, σ) yields the critical value, k: P( X k) = p.normalcdf(left bound, right bound) corresponds to P(left bound Z.normalcdf(left bound, right bound, μ, σ) corresponds to P(left bound X.normalpdf( x, μ, σ) yields a probability density function value, only useful to plot the normal curve, in which case " x" is the variable.− ∞ − ∞ uses the value –1EE99 for left bound.poissoncdf(λ, x) corresponds to P( X ≤ x).poissonpdf(λ, x) corresponds to P( X = x).To see a list of all probabilities for x: 0, 1.binomcdf( n, p, x) corresponds to P(X ≤ x).binompdf( n, p, x) corresponds to P( X = x).TI-83, 83+, 84, 84+ instructions for distributions and tests Distributionsįor technical assistance, visit the Texas Instruments website at and enter your calculator model into the search box.