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UF STA 2023 Exam 1 Questions and Complete Solutions Graded A+.
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UF STA 2023 Exam 1 Questions and Complete Solutions Graded A+.
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UF STA 2023 Exam 1Questions and Complete
Solutions Graded A+
Design - Answer: plan how to obtain the data
Description - Answer: summarize the data with graphs and numerical summaries
Inference - Answer: using data from a random and representative sample to draw conclusion about
population of interest
Subjects - Answer: persons, animals, or objects in our study/experiment
Variables - Answer: the characteristics that we measure on each subject
population - Answer: ALL subjects of interest
sample - Answer: subjects for whom we have data (small)
parameters - Answer: numerical summary of the population
statistics - Answer: numerical summary of the sample
categorical variables - Answer: place each observation into groups and they are usually summarized by
the percentage of observations in each group
,quantitative variables - Answer: take on numerical values
Key features of quantitative variables are the center (______) and spread (______) of observations in
each group - Answer: center=average
spread=variability
Discrete Quantitative Variable - Answer: take only a finite list of possible outcomes, such as a count
(0,1,2,3...etc)
Continuous Quantitative Variable - Answer: has an infinite list of possible values that form an interval,
even though sometimes we are limited in our ability to measure them
In 2010, the General Social survey had a question which asked respondents if they were willing to pay
higher prices to help the environment. In 2010, out of 1361 people, 8.2% said that they were very willing
and 14.6% said that they were not at all willing. Are "8.2%" and "14.6%" statistics or parameters? -
Answer: both are statistics
If someone is interested in examining the center,shape, spread and outliers of the quantitative data they
collected. What would be the appropriate graph to make of the sampled data? - Answer: dotplot
because the data is quantitative
How do you differentiate between skewed right and skewed left? - Answer: Trace your finger over the
outline of the data.If the tail goes to the right(higher numbers), it is skewed right. If the trail goes to the
left (lower numbers), it is skewed left.
Empirical Rule - Answer: The Empirical Rules states that about 68% of the data lies within one standard
deviation of the mean, about 95% of the data lies within two standard deviations of the mean and about
99.7% of the data lies within three standard deviations of the mean.
Suppose that you had the following data set.
100 200 250 275 300
, Suppose that the value 250 was a typo, and it was suppose to be 260. How would the value of the
standard deviation change? - Answer: it would mostly stay the same
Bar charts are used ONLY for ________data - Answer: categorical data
Finding r when given R squared - Answer: To find the value of r from R-squared.
First, change it to a decimal by dividing by 100.
Second, take the square root.
Third get the sign by looking at a graph or sign of the slope in the equation
Pie charts are used for ___________data - Answer: categorical
From 1975 to 1986, the General Social Survey asked its participants if they favored or opposed capital
punishment. A least squares regression line was calculated to predict the percent that favored the death
penalty based on the year. The least squares regression equation is yhat= -1859+0.9753x. Interpret the
slope for this equation. - Answer: Each year, the percent that favors capital punishment increases by
0.9753% on average.
A simple linear regression analysis was conducted to predict the Exam 3 score of students in STA 2023
based on their Exam 1 score.
The analysis yielded the following results:
y-hat = 50.57+0.4845x.
The range of exam scores for both tests was about 30 points to 102 points. Which of the following is the
best description of the y-intercept of the line(if appropriate)? - Answer: When the exam 1 grade
increases by 1 point, the exam 3 grade increases by 0.4845.
Find the equation of the Least Squares Regression line if:
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