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