Vocab
Probability
Z CI
T CI
Significance Tests
Misc.
100
Observations that are significantly different from other observations in a data set and may skew the results of statistical analysis
What are outliers?
100
The percent of marbles in a bag that are blue if 20% of the marbles are red, 5% are white, 30% are green, and 15% are black
What is 30%?
100
The critical value for 95% Confidence Level
What is 1.96?
100
The formula for a t confidence interval
What is x̄±t*(s/sqrt(n))?
100
The time it takes to download a video game is normally distributed with µ=2 hrs and σ=1hr. Dave believes it takes longer than 2 hrs to download a video game and so he randomly downloads 20 video games and finds the average time it takes to download a video game to be 2 hours and 30 minutes. What is the null hypothesis, alternative hypothesis, P-value, and statistical significance of the P-value at a significance level of α=.01
Ho: µ=2hrs, Ha: µ<2hrs, P=.0125, Not statistically significant and can not reject null hypothesis
100
Why did the chicken cross the road?
To get to the other side.
200
Two Samples where the groups are related.
What is a matched pairs design?
200
Consider the table below, which describes the probability that a randomly-selected dorm room has the given number of beds.
Give the probability of a dorm room having 3 or more beds.
What is 0.507?
200
The formula for the margin of error
What is z*(σ/sqrt(n))?
200
The sample size that gives a margin of error of at least 2 inches for a study of the length of rhinoceros horns that has a sample mean of x̄=8in and a sample standard deviation of s=1in with a t* value of 6.12.
What is 10 Rhinos?
200
A study is done that determines the length of geckos to be normally distributed with µ=7in Amanda believes the mean length of geckos is less than 7in and conducts her own study where she randomly measures 10 geckos and finds their mean length to be 6 inches and sample standard deviation to be s=1in. She conducts her study using a confidence level of 95% What is the null hypothesis, alternative hypothesis, P-value, and statistical significance of the P-value at a significance level of α=.05.
Ho: µ=7in, Ha: µ<7in, P=.00575, Statistically significant and reject null hypothesis
200
Road Work Ahead
Uh, yeah, I sure hope it does
300
The type of bias in this scenario: You (a researcher) send out a voluntary survey to all UO undergraduate students (~18,500) asking about their feelings on recent political occurrences, but you only get responses from students in politics clubs (800)
What is nonresponse bias?
300
You have a bed of marbles with 3 blue, 1 yellow, 4 red, and 2 green. Probability of drawing a blue or a yellow.
What is 0.4?
300
The upper limit of a 90% confidence interval of the trunk length of elephants if a study of 100 elephants has a sample mean of x̄=7ft with a standard deviation of σ=1ft
What is 7.1645ft?
300
The upper limit of a 96% confidence interval of a study of the weights of 20 sheep with a sample mean of x̄=200lbs and a sample standard deviation of s=100lbs
What is 249.3 lbs
300
A person wants to see if caffeine affects speed. The time it takes people to run 100 meters before and after caffeine is recorded below.
Is their speed significantly different at the 5% level?
No, p=0.43
300
The 5 original members of One Direction
Who are Zane, Harry, Louis, Liam, and Nial?
400
A numerical characteristic of a population, such as the population mean or population standard deviation
What is a parameter?
400
The probability that a randomly selected person listens to 11 hours to 16 hours of music or 2 hours to 4 hours of music if the amount of time people spend listening to music every week is normally distributed with µ=10hrs and σ=3hrs.
What is .3869?
400
The approximate sample size of a study of the time it takes hippos to walk up a hill if there is a 95% confidence interval of 7 minutes to 10 minutes with a standard deviation of σ=500 seconds
What is 119 hippos?
400
The approximate sample size of a study of the time it takes for people to get ready in the morning if the time it takes people to get ready in the morning has a confidence interval of 15 minutes to 50 minutes with a sample standard deviation of s=1500 seconds and a t* of 3.62
What is 27 people?
400
The significance of a study of the effects of sleep on college student test scores if scientists believe that having a good nights sleep causes students to score higher if the scientists took a a sample of 10 college students who did not get a lot of sleep before an exam and found their test scores had a x1=76 and s1=6 and a sample of 10 college students who did get a lot of sleep before an exam and found their test scores had a x2=84 and s2=8. Use a significance level of .05.
Statistically Significant, Reject Null Hypothesis, P=.0108976
400
Where can you find one-on-one stats tutoring?
4th floor of Knight Library