MAT-240 INTRODUCTION TO STATISTICS
MILESTONE 4
Two bags each contain tickets numbered 1 to 10. John draws a ticket from each bag
five times, replacing the tickets after each draw. He records the number on the ticket for
each draw from both the bags:
Bag 1Bag 2Draw 124Draw 245Draw 313Draw 464Draw 579
For the the first bag, the mean is 4 and the standard deviation is 2.5.For the second
bag, the mean is 5 and the standard deviation is 2.3.
Using the formula below or Excel, find the correlation coefficient, r, for this set of tickets
John drew. Answer choices are rounded to the nearest hundredth. - ANS-ANSWER IS:
0.75
For a set of data, x is the explanatory variable. Its mean is 8.2, and its standard
deviation is 1.92. For the same set of data, y is the response variable. Its mean is 13.8,
and its standard deviation is 3.03. The correlation was found to be 0.223.
Select the correct slope and y-intercept for the least-squares line. - ANS-Slope = 0.35
y-intercept = 10.9
Jesse takes two data points from the weight and feed cost data set to calculate a slope,
or average rate of change. A hamster weighs half a pound and costs $2 per week to
feed, while a Labrador Retriever weighs 62.5 pounds and costs $10 per week to feed.
Using weight as the explanatory variable, what is the slope of a line between these two
points? Answer choices are rounded to the nearest hundredth. - ANS-$0.13 / lb.
A bank manager declares, with help of a scatterplot, that the number of health
insurances sold may have some association with the number of inches it snows. How
many policies were sold when it snowed 2 to 4 inches? - ANS-350
Which of the following statements is TRUE? - ANS-High correlation does not always
imply causation.
Data for length of the tail (in millimeters) and age (in days) of tadpoles is entered into a
statistics software package and results in a regression equation of ŷ = 15 - 1.5x.
What is the correct interpretation of the slope if the length of the tail is the response
variable and the age is the explanatory variable? - ANS-The length of the tail decreases
by 1.5 millimeters, on average, when the tadpole's age increases by 1 day.
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