Unit 9
What is p-value?
The probability that a test statistic would take a value a extreme as more extreme than the one actually observed, assuming Ho is true.
Mean
The average of a data set, found by adding all numbers together and then dividing the sum of the numbers by the number of numbers
The 68-95-99.7 rule?
This rule helps to determine if data is normally distributed by checking the number of observations within each interval.
What is a binomial random variable?
This type of random variable requires a fixed number of trials.
Seven people are are seated in a row at the theater. Three have red hair. How many different ways are there to seat the people with red hair?
What is the null hypothesis (Ho).
The statement that is being tested.
Scatterplots
Graphs used to display the relationship between two quantitative variables?
What is correlation (or r)?
Measures the direction and strength of a linear relationship between two quantitative variables.
The type of variable where the probability distribution assigns probability as the area under the density curve above a specific interval.
A continuous random variable
Albert rolls a single six sided die 7 times. What is the probability that he gets a six in less than 12 rolls?
geomet cdf (1/6, 11) = 86.54%
What is type II error?
Accepting the Ho when it is actually false (a false negative).
What is a parameter?
A number that describes some characteristics of the population in statistical practices.
What is a power model?
Applying a logarithmic transformation to both variables causes this type of model to become linear.
When some groups in the population are left out of the process of choosing a sample
Under-coverage
Find the mean and standard deviation for a binomial distribution given n = 10, p = 0.8
mean = 8, std dev = 1.265
What percent of the population should the sample size be equal or less than in order to satisfy the independent condition?
10%
Define Sample list
The list of all possible outcomes.
What is the coefficient of determination (or r squared)?
The fraction of the variables in the values of y that is explained by the LSR of y on x.
The condition involving the population size that must be satisfied to use sigma divided by the square root of n as the standard deviation of a sampling distribution.
The population is at least 10 times the sample size
It is estimated that 45% of people in Fast-Food restaurants order a diet drink with their lunch. Find the probability that the first diet drinker of the day occurs before the 5th person.
geometcdf(.45, 4) = 0.908
What are the three conditions that need to be checked before running a significance test for a population proportion and a population mean?
Normal, random, and independent
What is test statistic?
A measurement of how far a sample statistic diverges from what we would expect if the null hypothesis (Ho) were true.
What is Simpson's Paradox?
Refers to the reversal of the direction of a comparison or an association when data from several groups are combined to form a single group.
The formula to determine the variance for a discrete random variable with three possible values.
Sigma sub x squared = (the square of the difference between x sub 1 and mu multiplied by p sub 1) + (the square of the difference between x sub 2 and mu multiplied by p sub 2) + (the square of the difference between x sub 3 and mu multiplied by p sub 3)
What is the probabiliuty that a randomly chosen subject completes more than the expected number of puzzles in the five-minute period while listening to soothing music?
Value: 1 2 3 4
Probability: 0.2 0.4 0.3 0.1
0.4