Statistics
Which is not a characteristic of the geometric mean as a measure of central tendency?
It is similar to the mean if the data are skewed right.
Which display is most likely to reveal association between a person's age and their salary?
Scatter plot
Using a sample to make generalizations about an aspect of a population is called
statistical inference.
The ordinary least squares (OLS) method of estimation will minimize
the distance between a straight line drawn through the data, and the distance from the data points to the line.
Events A and B are mutually exclusive when
their joint probability is zero.
Simple regression analysis means that
we have one variable (e.g., salary) that changes with the other (e.g., time on the job).
A local trucking company fitted a regression to relate the cost of its shipments as a function of the distance traveled. The Excel fitted regression is shown. https://fall18.elearning.jpcatholic.com/pluginfile.php/1726/question/questiontext/1712/3/909/Q3.3_graphic.png
143
Which of the following is not a characteristic of an ideal statistician?
Advocates client's objectives.
A line chart would not be suitable to display which data?
Annual compensation of the top 50 CEOs.
Which of the following statements is not true?
Estimating parameters is an important aspect of descriptive statistics.
Which is a not a characteristic of pie charts?
Exploded and 3-D pie charts will allow more "slices" and thus overcome a weakness of this technique.
A sample correlation of r = .40 indicates a stronger linear relationship than r = -.60.
False
Which of the following statements is not true?
For day-to-day data business analysis, even small companies rely on a large staff of expert statisticians.
"Men are taller than women. Dr. Jackson is a man, and thus he is taller than all the women in class." This statement best illustrates which fallacy?
Generalizing from an average to an individual.
The coefficient of correlation (r) does not have which property?
If there's no correlation between the data, r = -1.00.
Which is a reason for using a log scale for the Y-axis in time series data?
It helps compare growth in time for data of dissimilar orders of magnitude.
Thirty work orders are selected from a filing cabinet containing 500 work order folders by choosing every 15th folder. Which sampling method is this
Systematic sample.
From the data and the plot in the previous question, which is the correct statement?
There is a strong correlation between the data
Which is not an ethical obligation of a statistician?
To support client wishes in drawing conclusions from the data.
A scatter plot is used to visualize the association (or lack of association) between two variables.
True
The correlation coefficient r always has the same sign as b1 in Y = b0 + b1 X.
True
The correlation coefficient r measures the strength of the linear relationship between two variables.
True
When would an arithmetic mean ("average") be similar (i.e., almost equal) to a geometric mean?
When the data are all within the same order of magnitude.
If the fitted regression is Y = 2.1 X + 3.5 (R2 = .20, n = 100) it is incorrect to conclude that
Y is equal to 210 if X is equal to 100.
If samples are from a normal distribution with m (mean) = 100 and s (standard deviation) = 10 we expect
about 68 percent of the data are within 90 to 110.
The distribution pictured below is https://fall18.elearning.jpcatholic.com/pluginfile.php/1726/question/questiontext/1361/5/881/Statistics_Q2.5%20graphic.png
bimodal and skewed right.
Temperature in degrees Fahrenheit is an example of a(n) __________ variable.
interval
Your rating of the food served at a local restaurant using a 3-point scale of 0 = gross, 1 = decent, 2 = yummy is ___________ data.
ordinal
You use a four-point scale for rating your profesor, with 0= poor, 1= average, 2= good, and 3= excellent. The data are considered:
ordinal (ranked values)
A random sample is one in which the
probability that an item is selected is the same for all items in the sample population.
