Bias
"Do you agree that the new city parking fees are unfair and should be reduced?"
What is Voluntary Response Bias?
Law which states that as the number of repetitions of an experiment is increased, the relative frequency obtained in the experiment tends to become closer and closer to the theoretical probability.
What is the law of large numbers?
Number that represents the average of a population vs. number that represents the average of the sample
What is Parameter? What is a Statistic?
Listed are 29 ages for Academy Award winning best actors in order from smallest to largest.
18; 21; 22; 25; 26; 27; 29; 30; 31; 33; 36; 37; 41; 42; 47; 52; 55; 57; 58; 62; 64; 67; 69; 71; 72; 73; 74; 76; 77
Find the 70th percentile.
What is 64 years? Bonus: Interpret what the 64 years means according to the data.
A sample of 100 undergraduate San Jose State students is taken by organizing the students’ names by classification (first-year, sophomore, junior, or senior), and then selecting 25 students from each.
What is Stratified Sampling?
"How satisfied are you with our city's public transportation system?" (Survey conducted online only)
Suppose you pick four cards, but do not put any cards back into the deck. Your cards are QS, 1D, 1C, QD.
Did you use replacement or no?
What is "I used replacement"?
Data that describes categories or attributes of a population vs. Data that is always numbers
What is qualitative? What is quanitative?
Listed are 29 ages for Academy Award winning best actors in order from smallest to largest.
18; 21; 22; 25; 26; 27; 29; 30; 31; 33; 36; 37; 41; 42; 47; 52; 55; 57; 58; 62; 64; 67; 69; 71; 72; 73; 74; 76; 77
Find the percentile for 25.
What is the 12th percentile.
An administrative assistant is asked to stand in front of the library one Wednesday and to ask the first 100 undergraduate students he encounters what they paid for tuition the Fall semester. Those 100 students are the sample.
What is a convenience sample?
"How many hours per week do you volunteer in your community?" (Survey sent by mail with no follow-up for non-respondents)
Flip two fair coins. Find the probabilities of the events.
Let F = the event of getting at most one tail (zero or one tail).
Let G = the event of getting two faces that are the same.
Find the sample space first
S= {HH, TT, HT, TH}
A= P(F) = 34
B= P(G) = 24
x̄ vs μ
What is sample mean/ x bar? What is population mean/ mew?
During a season, the 40th percentile for points scored per player in a game is eight. Interpret the 40th percentile in the context of this situation.
What is "40 percent of players scored less than eight points in a game"
or "60 percent of players scored more than eight points in a game"
The first-year, sophomore, junior, and senior years are numbered one, two, three, and four, respectively. A random number generator is used to pick two of those years. All students in those two years are in the sample.
What is cluster Sampling?
"Don’t you agree that recycling is important for saving the environment?"
What does the complement of an event mean? ie. A′
What is "the opposite odds of probability that you could obtain that event."
Additional variable that could affect the outcomes of the actual study
What is a lurking variable?
In a sample of 60 households, one house is worth $2,500,000. Twenty-nine houses are worth $280,000, and all the others are worth $315,000. Which is the better measure of the “center”: the mean or the median?
What is the median?
A random number generator is used to select a student from the alphabetical listing of all undergraduate students in the Fall semester. Starting with that student, every 50th student is chosen until 75 students are included in the sample?
What is systematic sampling?
"Why do you think our brand’s new product is the best on the market?" (Survey conducted by the company that makes the product)
What is self-interest bias?
The sample space S is the whole numbers starting at one and less than 20.
Let event A = the even numbers and event B = numbers greater than 13.
P(A|B) = ___________, P(B|A) = _____________; are the probabilities equal?
P(A|B) = P(AANDB)/P(B) = 3/6, P(B|A) = P(AANDB)/P(A) = 3/9
What is "No, they are not equal"
Technique used in research to hide the control and experiment from the participants, other technique used to hide from the participant and researcher
What is blinding? What is double blinding?
Suppose that Rosa and Binh both shop at supermarket A. Rosa waits at the checkout counter for seven minutes and Binh waits for one minute. At supermarket A, the mean waiting time is five minutes and the standard deviation is two minutes.
Interpret it.
What is "Rosa's wait time of seven minutes is one standard deviation above the average of five minutes."
or
What is "Binh's wait time of one minute is four minutes less than the average of five minutes."
A completely random method is used to select 75 students. Each undergraduate student in the fall semester has the same probability of being chosen at any stage of the sampling process.
What is a simple random sample?