Hi,
p = .90, n = 183
TI syntax is binomcdf(n, p, largest x-value) for binomial ≤ cumulative probability
a) P(x <155) = binomcdf(183, .90, 154)= .0088
b) P(x ≥ 155) = 1 - binomcdf(183, .90, 154)= .9912
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