Download Z-Score Refresher

A little z-score refresher…
Name:
1. For a normal distribution, find the z-score location that separates the distribution as follows:
a) Separate the highest 30% from the rest of the distribution.
b) Separate the lowest 40% from the rest of the distribution.
c) Separate the highest 75% from the rest of the distribution.
2. Suppose that SAT scores among U.S. college students are normally distributed with a mean of
500 and a standard deviation of 100.
a) What is the probability that a randomly selected individual from this population has an
SAT score at or below 600?
b) What is the minimum score necessary to be in the top 15% of the SAT distribution?
c) Find the range of values that defines the middle 80% of the distribution.
A little z-score refresher…
Name:
1. For a normal distribution, find the z-score location that separates the distribution as follows:
a) Separate the highest 30% from the rest of the distribution.
b) Separate the lowest 40% from the rest of the distribution.
c) Separate the highest 75% from the rest of the distribution.
2. Suppose that SAT scores among U.S. college students are normally distributed with a mean of
500 and a standard deviation of 100.
a) What is the probability that a randomly selected individual from this population has an
SAT score at or below 600?
b) What is the minimum score necessary to be in the top 15% of the SAT distribution?
c) Find the range of values that defines the middle 80% of the distribution.
3. What percent of a normal population is more than 2 standard deviations above the mean?
Data for the rest: Adult women’s heights are ND with μ = 65.5 in (5′5½″) and σ = 2.5 in. 1′ = 12″ (one
foot = 12 inches
4. What percent of adult women have heights between 65.5 and 68 in (5′5½″ and 5′8″)?
5. What proportion of adult women have heights greater than 70.5 in (5′10½″)?
6. What’s the probability that a randomly selected adult woman is less than 63 in tall (5′3″)?
7. If a woman is 68 in (5′8″) tall, what’s her percentile rank?
3. What percent of a normal population is more than 2 standard deviations above the mean?
Data for the rest: Adult women’s heights are ND with μ = 65.5 in (5′5½″) and σ = 2.5 in. 1′ = 12″ (one
foot = 12 inches
4. What percent of adult women have heights between 65.5 and 68 in (5′5½″ and 5′8″)?
5. What proportion of adult women have heights greater than 70.5 in (5′10½″)?
6. What’s the probability that a randomly selected adult woman is less than 63 in tall (5′3″)?
7. If a woman is 68 in (5′8″) tall, what’s her percentile rank?