Data on Data on Data
When 2 variables are affecting the outcome of an experiment and their effects are indistinguishable, the variables are...
confounded
The probability of a person being between between 65 and 71 inches tall when the mean height is 68 inches and the standard deviation is 3 inches.
What is 68%?
The proportion of values between Q1 and the maximum.
What is 75%?
Bar graphs are a good way to represent quantitative data true or false
FALSE
All college graduates are THIS in a study to understand how much debt students had when graduating from college. The surveyors interviews 105 college graduates asking how much debt they had upon graduation.
What is the population?
A type of sample from a population that has groups and sub-groups. First, some groups are randomly selected, and then some sub-groups from within the selected groups are randomly sampled. Finally, individuals are randomly selected from within the sampled sub-groups. This can be extended to sub-sub-groups, etc.
What is multistage sampling?
Standard Deviations cannot be below this value.
What is 0?
In a right-skewed distribution, which is bigger, the mean or median?
The mean
What is the 5 number summary for the following data? Draw a boxplot to represent the data and comment on its shape.
4, 5, 2, 5, 3, 7, 2, 8, 2, 6, 3, 6,3, 2, 5
5 number summary:
2, 2, 4, 6, 8
Shape: Right-skewed
This measure of center is best for skewed data
The median
A Stat 121 study group consists of students with ages 18, 20, 21, and 25. If two additional
students ages 17 and 25 join the study group, what will happen to the mean and standard
deviation of the ages?
Mean stays the same
Standard deviation increases
The probability of a person being between between 60 and 65 inches tall when the mean height is 68 inches and the standard deviation is 3 inches.
What is 15.48%?
The 68-95-99 rule works for all distributions, normal or skewed. True or False?
FALSE
Referring to the histogram, what proportion of players scored more than 14 points?
5%
A table or graph that shows possible outcomes and how often those values occur.
What is a probability distribution?
A state television network wants to know which program is the most popular among viewers in the state. They take a random sample of 50 people from every county in the state. What type of study is this and what type of sampling method is used?
Observational study, stratified sampling.
2.5% of values are below 4 and 2.5% of values are above 8. These values are this many standard deviations away from the mean.
What is 2?
Given the following 5 number summary, are there potential outliers in the data?
21, 35, 65, 80, 95
No
A newspaper asks readers to write in their opinions on the new president elect. What kind of sampling technique is this?
Volunteer Sampling
In the 2008 Beijing Olympics, the United States won medals in both the Ladies Cross Country Skiing Team Sprint and the Ladies Speed Skating Team Pursuit. Cross Country skiing team times had a mean of 15.04 minutes with a standard deviation of 0.6 minutes. Speed Skating team times had a mean of 181.4 seconds with a standard deviation of 3.2 seconds. The U.S. cross country skiers' time was 13.94 minutes. The U.S. speed skaters' time was 189.3 seconds. Which team had a faster (lower) time, relative to other teams participating in their event?
Cross Country
Between what 2 values does 60% of the data lie, with a mean of 12 and standard deviation of 3?
9.45 and 14.55
Above what speed are 10% of track stars, knowing the mean speed is 10 mph with a standard deviation of 1 mph?
11.28 MPH
For a normal distribution, the proportion of values between 2 standard deviations below the mean and Q3.
What is 72.5%?
What kind of bias results from people refusing to participate in surveys?
nonresponse bias
The pH level of water is normally distributed with a mean μ = 7 and a standard deviation σ = 0.2. What proportion of blood has a pH level above 7.5?
0.0062