OA (Latest Update ) Questions
with Correct Answers {Grade A} 100%
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What does it mean when an individual data point has a z-score of +1? - correct answer
the data point is one standard deviation greater than the mean of the data set
A food chain finds that there is a strong positive correlation between average daily
sales for their pizza store and the number of daily visits to their website. What should
be considered before the pizza chain can conclude that the daily sales are driving the
number of visits to their website (or vice versa)? - correct answer is there a casual
relationship between sales and site visits?
We examine a population with normal distribution having a mean of 1000 and standard
deviation of 50. What percentage of the population lies between 900 and 1100? - correct
answer 95.4%
,We examine a population with normal distribution having mean of 1000 and standard
deviation of 50. What percentage of the population lies between 850 and 1150? - correct
answer 99.7
How are z-scores from a population with normal distribution distributed? - correct
answer normal distribution with mean 0 and standard deviation 1
A stock broker offers two portfolios for his clients. There are various risks with each
portfolio and his is trying to minimize the risk of loss. Both portfolios have the same
mean return. Which measure should the employee use to decide between these
alternatives? - correct answer variance
A comparison between the effectiveness of online vs. newspaper coupons was
conducted over a 3 month period to see which method brought in greater average
revenue per customer. Which statistic should the pizza manager recommend use to
determine promotional method to use? - correct answer T-test
,You are on soccer league with a total of 10 opposing teams, the pairings in the first
round are at random. There are 4 out of state and 6 in-state opposing teams. What is
the probability of playing against an in-state team? - correct answer 55.6%
Which type of distribution would you expect to see if mean=mode=median? - correct
answer normal distribution
Two variables are plotted on a scatterplot and the points on the plot closely follow an
upward, straight line. What is the likely correlation between the two variables? -
correct answer close to 1
Which of the following statistics are robust to minimize the effect of a single large
outlier? - correct answer median and interquartile range
correlation is not - correct answer causation
A good sample of the population being studied will be the right size and ___________ -
correct answer random
, If a sample is not random it creates ____________ - correct answer Measurement bias
If a sample if not the right size it creates _________________ - correct answer
measurement bias
Measuring the housing market in North Carolina when making an inference about the
entire East coast is an example of __________ - correct answer Non-representative
sample
Lemonade sales increase when it is warmer than 75 degrees. Weather and lemonade
are __________ - correct answer correlated
Pulling names from a hat is a tool to create a ______ sample - correct answer random
Asking participants to taste test a yellow candy and a blue candy and select one can
create bias. How can we prevent bias? - correct answer blinding