ci_low, ci_upp = proportion_confint (count, nobs, alpha=0.05, method='normal') Where the parameters are: count (int or array_array_like) – number of successes, can be pandas Series or DataFrame nobs (int) – total number of trials alpha (float in (0, 1)) –. Examples of percentage percentage Students scoring as proficient or advanced were at the highest percentages last year in math, science, reading and writing. From MLive.com There will. Sampling Distribution of the Sample Proportion. Condition 1: Simple Random Sample with Independent Trials. If sampling without replacement, N ≥ 10n. Verify that trials are independent: n ≤ 0.05N. Condition 2: Large sample size with at least 10 successes and 10 failures. np ≥ 10 and nq ≥ 10. Given: p, p̂, n. To Find: q, μ p̂, σ p̂.