Variables
Z-Scores
Distributions
Confidence Intervals
100
What variable is represented by the letter n?
Sample Size
100
Given a mean of 80, and a standard deviation of 6: What is the Z-Score for a raw score of 92?
2
100
Find P(Z<1.75)
.96
100
When 360 college students are randomly selected and surveyed, it is found that 120 own a car. Find a 90% confidence interval for the true proportion of all college students who own a car.
.29<P<.37
200
What variable is represented by 
Sample Mean
200
Given a mean of 72, and a standard deviation of 9: What is the Z-Score for a raw score of 60?
-1.333
200
For a data set with a mean of 200 and a standard deviation of 16, find P(190<x<220).
.63
200
A random sample of 300 full-grown lobsters had a mean weight of 15.8 ounces and a standard deviation of σ=3.2 ounces. Construct a 95% confidence interval for the population mean, μ.
15.4<μ<16.1
300
What variable is represented by μ (Mu)?
Population Mean
300
What Z-Score would one need in order to be in the top 50% of data points?
0
300
For a data set with a mean of 330, a standard deviation of 52, and a sample size of 30; What is P(X>332)?
.42
300
A survey of 450 students from a New York State School District reveals that 198 favor year round school with two week vacations every ten weeks. Construct the 90% confidence interval for the true population proportion of all New York students who favor year round school.
.402<P<.478
400
What variable is represented by σ?
Population Standard Deviation
400
A Student has a Z-Score of 1.8 on their recent exam. The average for the exam was 77, with a standard deviation of 8. What did the student score on the exam?
91.4
400
A fruit-filled cereal is packaged in boxes that contain an average of 450 grams and for which the standard deviation is 12 grams. A sample of 36 boxes is randomly selected. Find the probability that the sample mean will be at least 454 grams.
.023
400
Of 150 randomly selected adults over thirty who frequent a very large mall, 10% admitted to having lost their car at the mall. Construct a 95% confidence interval for the true percentage of all adults over thirty who shop at that mall who admit to having lost their car at the mall.
.05<P<.15
500
What variable is represented by p̂ (P-Hat)?
Sample Proportion
500
A recent test had an average score of 82, with a standard deviation of 5. What would grade would one need to score in the top 10%? (Round to nearest tenth)
88.4
500
An online retailer claims that 90% of all orders are shipped within 12 hours of being received. A consumer group placed two hundred orders of different sizes and at different times of day; Find the probability that at least 185 of these orders are shipped within 12 hours of being received.
.119
500
The heights of thirty Giraffes were measured, and found to have a mean of 17' 6" feet, with a sample standard deviation of Sx=9". Construct a 90% confidence interval for the true mean height of all giraffes.
17.27<μ<17.73
(17' 3.24"<μ<17' 8.76")