Type the R transcript that returns P(X < 138) and P(X > 99) for X ~ N(120, 15²) — note the sd argument and lower.tail = FALSE.
Type the R transcript that returns P(X < 138) and P(X > 99) for X ~ N(120, 15²) — note the sd argument and lower.tail = FALSE.
Answer
> pnorm(138, mean = 120, sd = 15) [1] 0.8849303 > pnorm(99, 120, 15, lower.tail = FALSE) [1] 0.9192433
pnorm is the cdf in the original units — the third argument is σ = 15, not σ² = 225. lower.tail = FALSE returns P(X > 99) directly, the 0.9192 of L7.3 without the 1 −.
R documentation for pnorm/qnorm (EXT); every R line is the verbatim console text of a real Rscript run (2026-09-17); H-W7 (qnorm(0.95) check) — shape only; original dataset