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Data Analytics Final Exam Correct Questions and Answers 2025.
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Data Analytics Final Exam Correct Questions and Answers 2025.
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Data Analytics Finalwhat are the usual levels for a confidence interval? - ANS90, 95, 99
what must we assume to estimate a confidence interval? - ANSthat the data points were generated by a
random process and that the underlying distribution is standard normal.
The SEC requires companies to file annual reports concerning their financial status. It is impossible to
audit every account receivable. Suppose an auditor audits a random sample of 49 accounts receivable
invoices and finds a sample average of $128 and a sample standard deviation of $53. What is the 95%
confidence interval for the mean size of an accounts receivable invoices? - ANS$22-232
Suppose I have a theory that sprinkling some sea-salt over the brownies I just baked will improve their
taste. What is the null hypothesis? Is this a one-tailed or two-tailed test? - ANSThe null is that there will
be no change to the taste. The test would be one-tailed.
Type I errors are usually more costly since they involve: - ANSchanging the status quo
erring on the side of which kind of errors is more common? - ANStype II
What does it mean when a p-value is small? - ANSThere is enough evidence to reject the null hypothesis
in favor of the alternative
The coefficient is likely to be statistically significant
The probability of making a type I error is low
Which of the following is not a good situation for using regression analysis?
A ) answer the question of whether or not to fire an employee
B ) To understand the determinants of a stock price, such as its past values
C ) To predict the selling price of a house using multiple explanatory variables
D ) To explain how a firm's revenues depend on advertising and marketing expenditures - ANSA
, T/F A successful regression analysis guarantees that the explanatory variables cause the dependent
variable, since reverse causality and/or omitted variables are accounted for. - ANSFalse
How is the best-fit line chosen in regression analysis? - ANSMinimizing the sum of squared residuals
What is the difference between an error and a residual in the regression context? - ANSResiduals can be
calculated from the observed data, but errors cannot
T/F Homoscedasticity refers to a non-constant error variance, or "fan" shape, while heteroscedasticity
states that the variation of the Y's around the regression line is the same. - ANSFalse
Consider the simple linear regression equation:
Y=α+β1X1+ϵY=α+β1X1+ϵ
What are αα and ββ? - ANSThey are the regression coefficients
Which of the following is an example of time series data?
A ) The Census Pulse dataset, with multiple households tracked for multiple weeks
B ) The stock allocations in a portfolio in a given time frame
C ) The hourly flow of customers through a cafe
D ) The unemployment rates of each country - ANSC
what are some of the challenges to using time series data in statistical modeling? - ANSAutocorrelation,
meaning that time series variables are correlated with themselves
The fact that all data points are historical, so conditions may have changed
Most time series trends also include noise, which can make them difficult to predict
what is the difference between seasonal trends and cyclical trends? - ANSseasonal trends are predictable
patterns in the time series data
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