Although regression can be used to forecast time series, what would be a drawback of using regression?It violates independent error assumption.
It is generalizable to handle error dependence.
It is simple to calculate by hand.
Both a and c
When a time series dataset shows an increasing variability, what would be an appropriate first step to
make the variability constant?
Group of answer choices
Difference the dataset
Take the logarithmic transformation
Multiply the dataset by a small number such as 0.001
Divide the dataset by a large number such as 10,000
What is an advantage of moving average and/or exponential smoothing?
Group of answer choices
Moving average requires selection of optimal period.
It performs well for horizontal patterns.
Exponential smoothing requires selection of optimal smoothing constant.
Both a and b
Consider the following partial dataset.
Date
Closing price
Return
9/1/2018
3000
—
9/2/2018
2985
?
9/3/2018
2891
-3.15%
Calculate the return series for 9/2/2018.
0.5%
-0.5%
3.15%
-5%
Which one of the following represents a stationary time series?
Group of answer choices
A household’s monthly electricity bill (in dollars) for four time periods is 500, 300, 401, and 460,
respectively. Calculate the 3-period moving average forecast for period 5.
Group of answer choices
400
387
350.5
310
A k-period moving average uses __________.
Group of answer choices
the mean of the time series values for the most recent k periods to forecast the time series value for the
next period
the mean of the time series values for the most recent k – 1 periods to forecast the time series value for
the next period
the mean of the time series values for the most recent k + 1 periods to forecast the time series value for
the next period
None of these
Can a 3-period moving average forecast be made for period 3?
Group of answer choices
Yes
No
It depends on one dataset to another.
Cannot be determined
Suppose that regression was used to predict the sales (in thousands). The regression equation is given
by
Y = 200 + 21t
Forecast the sales for the period 20.
Group of answer choices
$620
$2,000
$600,000
$620,000
An exponential smoothing forecast is ___________.
α times the most recent period’s time series value, plus (1 – α) times the most recent period’s forecast
value, where α is a smoothing constant
between 0 and 1
α times the most recent period’s time series value, plus (1 – α) times the most recent period’s forecast
value, where α is a smoothing constant
between 0 and 10
α times the most recent period’s time series value, plus (1 – α) times the most recent period’s forecast
value, where α is any positive smoothing constant
α times the most recent period’s time series value, plus (1 – α) times the most recent period’s forecast
value, where α is any negative smoothing constant
Let Ha: the average stock price is not $5. Based on a sample, we calculated the test
statistics to be -3.31 with the p-value of 0.0091. However, if we wanted Ha: the average
stock price is less than $5 then what would be the p-value?
Group of answer choices
0.0091
2*(0.0091)
0.0091/2
0.05
Would a 90% confidence interval for a population mean be narrower or wider than the
corresponding 95% interval?
Group of answer choices
narrower
wider
same
cannot be compared
Based on the research question below, determine the type of hypothesis test.
Does the sales training have any effect on the company’s sale amount?
Group of answer choices
Left-tailed
Right-tailed
Two-tailed
None of the above
A p-value is defined as _________.
the probability that the observed, or more extreme, results when the alternative
hypothesis is true
the probability that the observed, or more extreme, results when the null hypothesis is
true
the probability that the observed, or more extreme, results when the null hypothesis is
false
the probability that the observed, or more extreme, results when the null hypothesis is
either true or false
Which one of the following is a correct hypothesis?
Group of answer choices
H0: the average stock price is $25.
H0: the average stock price is less than $25.
H0: the average stock price is not $25.
H0: the average stock price is greater than $25.
In probability theory, _____________ states that the sampling distribution of the mean
will be approximately normal when we have a large sample.
Group of answer choices
the confidence interval
the p-value
the test statistics
the Central Limit Theorem
A fundamental question in the analytics is the question of statistical significance. Which
one of the following best describes the statistical significance?
Group of answer choices
Are the sample statistics extreme enough to infer a conclusion about the sample?
Are the population parameters extreme enough to infer a conclusion about the
population?
Are the sample statistics extreme enough to infer a conclusion about the population?
None of the above
We want to give a title for the SAS output. Which statement is a correct way to include a
title?
Group of answer choices
TITLE “Summary Statistics for Business Sale”;
TITLE:Summary Statistics for Business Sale;
TITLE; “Summary Statistics for Business Sale”;
‘Summary Statistics for Business Sale’;
Suppose we have two groups and want to produce descriptive statistics for these two
groups separately. Which statement allows us to do this?
Group of answer choices
VAR statement
OUTPUT statement
CLASS statement
BY statement
In PROC MEANS, what keyword is needed to produce the number of missing
observations?
Group of answer choices
N
NMISS
MEAN
LCLM
An analyst surveys 1,000 registered nurses across the U.S. and computes their mean
earnings to be $27 per hour. The analyst reports that U.S. nurses have mean earnings
of $27/hr. The 1,000 nurses are a __________.
population
sample
parameter
statistics
In human resource management, performance of employees is measured as a
numerical score which is assumed to be normally distributed. The mean score is 150
and the standard deviation 13. What is the probability that a randomly selected
employee will have a score less than 120? You can use the following website to
calculate the probability. https://stattrek.com/online-calculator/normal.aspx (Links to an
external site.)
Group of answer choices
0.489
0.011
0.251
0.552
In human resource management, performance of employees is measured as a
numerical score which is assumed to be normally distributed. The mean score is 150
and the standard deviation 13. What is the probability that a randomly selected
employee will have a score between 120 and 150? You can use the following website to
calculate the probability. https://stattrek.com/online-calculator/normal.aspx (Links to an
external site.)
Group of answer choices
0.50
0.011
0.251
0.552
An analyst obtains the salaries of all 200 federal appeals court judges in 2017 and
computes the mean salary to be $215,000. The $215,000 is a __________.
Group of answer choices
population
sample
parameter
statistic
In a survey, the probability of response “Yes” is ⅔ and “No” is ⅔ . If 10 people are
surveyed, what is the probability that at least 3 (greater than or equal to 3) people will
respond “Yes.” Use the following website to answer the
question. https://stattrek.com/online-calculator/binomial.aspx (Links to an external site.)
Group of answer choices
0.0162
0.0197
0.9803
0.9966
Suppose you play a game of chance in which five numbers are chosen from 0, 1, 2, 3,
4, 5, 6, 7, 8, 9. A computer randomly selects five numbers from 0 to 9 with replacement.
You pay $2 to play and could profit $100,000 if you match all five numbers in order (you
get your $2 back plus $100,000). Over the long term, what is your expected profit of
playing this game?
Group of answer choices
About -$1.00
About $0
About -$2.00
About -$200,000.
Suppose that a random variable X is defined as the number of “Yes” responses from a
survey with 100 questions. What is the most appropriate probability distribution?
Group of answer choices
binomial distribution
normal distribution
Poisson distribution
uniform distribution
In a survey, the probability of response “Yes” is ⅔ and “No” is ⅔ . If 10 people are
surveyed, what is the probability that at most 5 (less than or equal to 4) people will
respond “Yes.” Use the following website to answer the
question. https://stattrek.com/online-calculator/binomial.aspx (Links to an external site.)
Group of answer choices
0.0765
0.1365
0.2131
0.9235
A coffee shop owner wants to examine the number of customers who pass in front of
his store in the morning from 7:00am to 7:30am. Suppose that the mean number of
customers during this time window is 200. What is the probability that more than 210
people will pass in front of his store? Use the following website to compute the
probability: https://stattrek.com/online-calculator/poisson.aspx (Links to an external site.)
Group of answer choices
0.2272
0.7512
0.7727
0.0215
In the binomial probability distribution, the binomial coefficient gives the number of ways
to arrange items when the order doesn’t matter. That is, suppose we have four letters
{A, B, C, D} and we choose two letters, therefore, there are 6 ways to have a two-letter
word. Now, suppose we have five letters {A, B, C, D, E}. How many ways to choose
three-letter words?
Group of answer choices
131
12 ways.
14 ways.dd
10 ways.
