Vocab
The difference in the middle 50% of the data when the data has been sorted in ascending order.
Interquartile Renge
Number of siblings
Discrete Quantitive
A survey regarding download time on a certain website is administered on the Internet by a market research firm to anyone who would like to take it.
Convenience (no random and not systematic)
A survey was sent out to 5000 people and only 250 responses were received.
Nonresponse (sent out a lot but only got a little back)
What is the population: A quality control manager randomly selects 50 bottles of Coca-Cola that were filled on a given day to determine the calibration of the filling machine.
The average difference between the data and the mean.
standard deviation
Grams of carbohydrates in a doughnut
Continuous Quantitate
In an effort to identify if an advertising campaign has been effective, a marketing firm conducts a nationwide poll by randomly selecting individuals from a list of known users of the product.
Simple Random (no grouping, not systematic, random selection)
After a survey was conducted it was determined that one of the questions was written in a very confusing way which lead to some answers that might not truly represent the correct response.
Measurement (poorly worded questions that lead to bad data)
What is the sample: A survey was done of 1028 teenagers that live in the US and they were asked whether or not they suffered from anxiety.
1028 teenagers that live in the US
Probabilities that are calculated by counting the number of times something occurs in a set of data that was collected.
empirical probability
Width of a parking space
Continuous Quantitative
To estimate the percentage of defects in a recent manufacturing batch, a quality-control manager at Intel selects every 8th chip that comes off the assembly line starting with the 3rd chip until she obtains a sample of 140 chips.
systematic (every 8th chip)
FREE SPACE
YAY
A set of events where there are no outcomes that can fall into more than one event.
mutually exclusive
Phone Number
Categorical
A member of Congress wishes to determine her constituency’s opinion regarding estate taxes. She divides her constituency into three income classes; low-income households, middle-income households, and upper-income households. She then takes a random sample of 200 households from each income class.
Stratified (grouping and then randomly select from each group)
A company wants to do a survey on consumer satisfaction and sends surveys to customers that have ordered multiple times from the company (all one time customers were excluded).
temperature
The type of statistics that refers to methods used to make decisions or predictions about a population.
Inferential Statistics
Nation of orgin
Categorical
To determine the prevalence of human growth hormone (HGH) use amount high school varsity baseball players, the State Athletic Commission grouped everyone by the high school they attend then randomly selects 50 high schools. All members of the selected high schools’ varsity baseball teams are tested for HGH.
Two different statistics students conducted well designed studies to determine the proportion of students at the university who are in favor of canceling classes on Friday when there is a Thursday night home football game. One student reported a sample proportion in favor as 67% while the second student reported a sample proportion in favor of 82%.
Sampling (2 different studies that lead to two different results)
type of clothing purchased at a store