Portage Learning Statistics Module 4 Z Test 2026 Study Guide Comprehensive

PORTAGE LEARNING STATISTICS MODULE 4 Z
TEST 2026 STUDY GUIDE COMPREHENSIVE

◉ 68-95-99.7 rule Answer: in a normal model, about 68% of values
fall within 1 standard deviation of the mean, about 95% fall within 2
standard deviations of the mean, and about 99.7% fall within 3
standard deviations of the mean


◉ In a normal distribution, ____ number of values fall above and
below the mean. Answer: same


◉ In a normal distribution, the ____ area under the curve on both
sides. Answer: same


◉ z score Answer: aka standardized score; indicates how many
standard deviations a raw score is above or below the mean


◉ raw score Answer: the actual, observed score


◉ The positive or negative sign in front of the z score indicates...
Answer: whether the raw score is above or below the mean

, ◉ The value of the z score indicates... Answer: how many standard
deviations a raw score is from the mean


◉ Z score of mean Answer: 0


◉ formula for z-score in the population Answer: z=(X-μ)/σ


◉ formula for z-score in the sample Answer: z=(X-x̄ )/s


◉ The z-score can help us compare scores from 2 different... Answer:
populations or samples or scores measured on 2 different scales


◉ formula for converting z-scores in the population Answer: X=
μ+zσ


◉ formula for converting z-scores in the sample Answer: X=x̄ +zs


◉ We can convert sample means into.... Answer: z-scores


◉ formula for converting sample means into z-score Answer: z= (x̄ -
μ)/[σ/squareroot(n)]