C207 Module 5 & 6- Study Guide
IN a small African town of 1,000 people, a total of 100 people have died of Ebola, and of these 20 have died in the last month. in this case, the prevalence and cumulative incidence of ebola in this town are...
.10 and .02 respectively
Breakeven Analysis Essentials (3 total)
1-Fixed costs 2- variable cost 3- Revenue
We have a linear regression equation that predicts power usage per year. The equation is: y = 50 +10x. If I wan to know the usage for year 10, the model forecasts which of the following...
150
If the restaurant sales average $100,000 per month and the standard deviation is $10,000, what is the probability that sales will be less than $90,000 in any given month?
16.7%
Suppose that you want to express the average cost of gas in Jan. 2015 ($2 per gallon) to that in July 2008 ($4 per gallon) as a simple index number. Then the value would be...
50
Suppose that scores for a particular exam follow a standard normal distribution. Approximately what percent of the scores should fall within +/- 2 standard deviation from the mean?
95%
In the middle of an online exam, the power goes off and only the questions answered to that point are graded. For the resultant exam score the power going off...
A introduced systematic measurement error
There are three elementary schools in a community and the third grade students take a standardized math test. Which tool would help us analyze whether all three of the schools' students perform similarly on this math test or whether the performance of the students at one school is statistically different than the other two schools?
ANOVA
Test-retest Method
Applies when the same test is given to the same sample on two different occasions.
Parallel-Forms Method
Applies when two versions of a test are given at the same time to each of half of a sample of students.
Homoscedasticity
Assumes that the variance of a dependent variable is consistent across the range of values.
Cross Over Analysis
Best cost for volume produced(Used with 3 products) Key Word: VOLUME
Netflix has an algorithm to come up with recommended movie titles for its subscribers. It does so by making use of...
Big Data
Which of the following would describe a data distribution that has two peaks and is otherwise symmetrical?
Bimodal distribution
An entrepreneur has a great idea. She has researched the startup costs and cost of providing the product to potential customers, and she has researched the market and determined the price it will sell for. If the entrepreneur wants to know the minimum capital she will need to make the business a success, which tool would help with that analysis?
Breakeven Analysis
Dependent variable
Calculated from the value of the other variables in an equation.
Random Measurement Error
Can eventually be eliminated over time as the number of tests increases (according to Classic Test Theory)
A marketing department wants to know how to group their potential customers so they can deliver tailored messages to each group with the hope they will better receive the message and respond with higher purchases. Which analysis tool will help them create the groups?
Cluster Analysis
Criterion-referenced test
Compares an individual to certain defined standards.
A company wants to provide a new service. There are three computer companies providing three different solutions to enable them to implement the new service. If they want to know which one will be least Expensive at the Volume of service they expect to provide each year, which Analysis tool will help with this situation?
Crossover Analysis
We have a situation where we have to make some decisions, interspersed with a series of events that we do not control. Which tool will help us make a better decision?
Decision Analysis
Autocorrelation
Describes events whose probability of occurring depends upon the events that occurred previously.
Cyclicality
Describes results that go up and down periodically, but don't necessarily follow the calendar.
Random variation
Describes the variability that occurs in events for which we have no explanation.
Seasonality
Describes variability in a process that occurs at the same time of year each year
Standard Score
For a particular data point, represents the distance from the mean in terms of standard deviations.
Z-Scores always have a mean of 0 and a standard deviation of 1.
For an ANOVA, the larger the F-Ratio, the more likely there is a statistically significant difference.
William scored 30 on a test with a mean of 20 and a standard deviation of 10. On a second test, he scored a 50 on a test with a Ean of 35 and a standard deviation of 15. in terms of standard scores...
His standard scores are the same for both tests
Which of the following best represents a null hypothesis from an ANOVA?
Ho: u1 = u2 = u3
Linear Programming finds a maximum or minimum solution in a situation that has various constraints.
If we are analyzing which among three equipment options for a new office would be the best choice, we might use crossover Analysis
Which of the following is the last step of Result-Based Management?
Impact
True Score Theory States that...
In a test without systematic error, the observed score is the true score.
Percentile
Indicates the percent of the population that falls below a certain value.
Statistical population
Is a group of observations that have something in common.
Norm-referenced test
Is a test that compares an individual to other individuals on the bell-shaped curve.
Independent variable
Is a variable in an equation to which we can assign a specific value.
Mean
Is the average of a group of measurements.
True Score
Is the average score an individual would achieve if he or she were to take the test infinite times.
Observed Score
Is the score actually achieved by an individual on a test.
Item analysis
Is the study of the results of each individual question on a test.
Analysis of Variance (ANOVA)
Is used to determine if three or more sample means are statistically not all equal
A fast-food company has three products they provide their customers from he same kitchen area. They want to maximize their profits by determining the production mix that best uses their limited numbers of grills and other equipment. Which analysis tool will help them make a great decision?
Linear Programming
Outlier
Measurement that is very different than other measurements of similar events.
Reliability Index
Measures how well a person's observed score on a test represents that person's true score.
In a crossover Analysis Considering three options, NOT every crossover point is essential to our analysis.
Non-relavant Point(when it doesn't affect the analysis)
Systematic Measurement Error
Occurs when something that is entirely unrelated to the test is affecting test scores
Irregularity
Occurs when there is a one-time unusual measurement in a process.
Linear Programming
Often used to find the combination of products that will Maximize Profits or Minimize Costs. Key Word: PRODUCTION MIX
Which of the following is described by correlation?
One variable is related to the other variable
Which of the following statistical tests helps us understand the probability of our being wrong if we reject the null hypothesis?
P-Value
Which of these takes a life-cycle approach?
Results Based Management
A company sales peak each July. They should correct their Exponential Smoothing forecasts using which of the following:
Seasonality
Break even
Shows the number to produce before you make a profit
Which of the following are vital to a Result-Management system's success?
Simplicity, Flexibility, transparancy
Item Response Theory
Takes into account that different questions may have different levels of difficulty
Heteroscedasticity
The assumption that the variance of a dependent variable changes across the range of values.
X squared
The key statistic for a Chi Square analysis
R-squared
The key statistic for a Regression and time series.
t-stat
The key statistic for a T-test
F-Value
The key statistic for an ANOVA analysis
Median
The midpoint value of a group of measurements.
Mode
The most common measurement of a group of events.
Cluster Analysis
The process of arranging terms or values based on different variables into "natural" groups. Mostly used in Marketing. Key Term: GROUPS
Average High school senior math assessment scores differs significantly between schools. A college admission office wants to understand a students performance relative to his/her classmates from their particular school. In this case, the most appropriate measure is...
The students percentile score for their school.
A study of income shows that the range of income for a population has a Wider range as those people increase in age. Which of the following issues is present and what do we do about it?
This shows Heteroscedasticity and we use Regression
Analysis of variance (ANOVA)
Verifies if multiple populations of data are the same or at least one is different than the others.
Dependent variable
Which of the following represents the prediction in a regression problem.
Incidence Rate
Would be used if we want to measure the proportion of health workers who acquire ebola from working with ebola patients.
A normal Distribution uses the Z-score to determine probabilities of various events. If we want the upper tail to contain 2.5 of all possible outcomes, which value of Z would we use?
Z = 1.96
In calculating an index number, the denominator is generally a price from:
a base period
Trend
is general direction in which something is developing or changing.
Giving the same test to the same sample at two different times would be an example of...
test-retest method
A gender ratio is
the number of males divided by the number of females.
Decision Tree
the process of weighing all outcomes of a decision to determine the Best Course of Action.
John creates an aptitude index in which he gives 60% importance to a verbal performance measure and 40% importance to a quantitative performance measure. John should create a
weighted composite index