Chapter 1
What is the difference between descriptive statistics and inferential statistics?
Descriptive statistics is the collection, organization, and summarization of data while inferential statistics is a generalization from samples to populations and determining relationships between variables.
If the number of data points for class 45-50 is 5 and the number of data points for class 51-56 is 7, what is the frequency of class 51-56?
7
What is the difference between μ and X bar?
μ is the population mean while X bar is the sample mean.
What is the difference between a simple event and a compound event?
A simple event has only 1 outcome while a compound event can have 2 or more outcomes.
What is the Hawthorne effect?
The Hawthorne Effect is the modification of behavior by study participants in response to their knowledge that they are being observed or singled out for special treatment. This results in increased output that responds favorably to the researcher.
Qualitative variables are variables that have distinct categories based on a characteristic. What are quantitative variables and what are the 2 types?
Quantitative variables are variables that can be calculated or measured. The 2 types are discrete and continuous.
With a class limit of 14.25-16.25, what are the class boundaries?
14.245-16.255
The median is the half way point in the data set and the midrange is the average of lowest and highest values in a set. What kind of mode is there when there are 2 modes?
Bimodal
Unimodal is 1 mode
Multimodal is 3+ modes
Why can probability not be numbers such as 35, 48, or 1.2?
Total probability is 1 so values can only exist between 0 and 1.
What is the coefficient of variation?
The mean number of cookies sold at a bakery was 124 and the standard deviation was 11.
8.9
While and experimental study has a variable being manipulated to study the outcome, what is the difference between the observational studies: Cross-Sectional, Retrospective, and Longitudinal?
Cross-Sectional: Data is collected at one time
Retrospective: Data is collected using records from the past
Longitudinal: Data is collected over a long period of time.
With a max value of 112 and a min value of 87, what is the class width of the sample? With 6 classes desired.
5
How do you go from sample variance to sample standard deviation?
And from population standard deviation to population variance?
You square root s2 to find s.
You square σ to to find σ 2.
What is the notation for probability?
P(E) = n(E)/n(S)
number of outcomes in Event E divided by number of outcomes in the sample space S
The probability that Samantha will be accepted to the college of her choice and get a scholarship is 0.35. If the probability that she gets accepted to college is 0.65, find the probability that she will obtain a scholarship given that she is accepted by the college.
0.538
What are the 2 types of qualitative levels of measurement and the 2 types of quantitative levels of measurement?
The 2 types of qualitative measurements are nominal and ordinal while the two quantitative measurements are interval and ratio.
Nominal: Eye color, male/female, etc.
Ordinal: Movie ratings, letter grade, etc.
Interval: Temperature, IQ score, etc.
Ratio: Height, weight, etc.
Between a histogram, a frequency polygon, and an ogive, which graph uses upper-class boundaries on the x-axis and cumulative frequencies on the y-axis?
Ogive
Frequency Polygon: midpoints and frequencies
Histogram: class boundaries and frequencies
A test is administered to 11 students, which was out of 30 points. The score resulted as: 21, 15, 12, 30, 28, 10, 23, 25, 21, 6, 25. What is the percentile rank of the score 23?
Round to nearest whole number.
59th percentile
What is the sample space for flipping 3 coins?
S = {HHH, HHT, HTT, HTH, TTT, TTH, THH, THT}
In a recent survey, 25% said they felt underqualified for their job. Of these, 78% of then resigned. If a person is randomly selected, find the probability that someone will feel underqualified but still resign.
0.195
What are the 4 types of sampling techniques and their definitions?
Random: all members have equal chance of being selected.
Systematic: every kth person of the population gets selected.
Stratified: population is divided into subgroups based on a characteristic, and then are randomly selected within that group.
Cluster: population is divided into sections and then one or more whole sections are chosen.
The distribution that has most of the data located on the right side is a ______ skewed distribution. It also be known as: positively or negatively skewed?
Left, Negatively
A way to remember: Left skewed has its tail on the left.
What numbers are a part of the five number summary? And where does each number go on a box plot?
Minimum, maximum, Q1, Q2/Median, and Q3.
How many outcomes would there be if I rolled 3 dice?
216
A class of 25 students took a science test. 10 students had an average score of 80, while the other students had an average score of 60. What was the average score of the whole class?
68