STAT 1450 Recitation Activity 3 Student Name: Angelica Quebatay
Normal Distributions TA: Sarah Balfour
Date#: 09/06/23
OBJECTIVES
Students will review select concepts regarding density curves.
Students will apply the 68-95-99.7 Rule.
Students will use Table A to compute proportions of a Normal Distribution.
Students will explore the Normal Density Curve Applet.
Part I: TRUE/FALSE Please correct any false statements.
1. Density curves have areas of exactly 1 beneath them. T
2. The probability that a uniformly distributed random variable assumes values above its
maximum is greater than the probability that it assumes values below its minimum. F
3. For a normal distribution, the mean is an appropriate measure of spread and the standard
deviation is an appropriate measure of center. T
4. The invNorm function on the graphing calculator computes probabilities associated with
the normal distribution. F
5. The Standard Normal Distribution has a mean of 1 and a standard deviation of 0. F
6. The formula x = +z is used to find a value, x, when given a percentile associated with a
particular Normal() distribution. -> T
7. Under a normal curve, the area below -1.5 is the same as the area above 1.5. T
Part II: Z-Score Comparison
8. Assume that ACT-Math scores are distributed N(20.2, 5.8) and SAT-Math scores N(521,
100). An aspiring Statistician wants to submit her best score on college applications. If she
earns a 30 on the ACT-Math and a 700 on the SAT-Math, which score is superior?
The SAT score of 700 would be more superior than the ACT score of 30 since the
SAT has a higher z-score (1.29) than the ACT score (1.69). A higher z-score means
a better performance than the mean.
STAT 1450 Recitation 3 p.1
