1. multple choice answer the A, B, C, D find the answer and
answer the reason for why it is true
A. Which of the following statements is
true?
(2)
- The correlation coefficient (r) equals the proportion of times
two variables lie on a straight line.
- The correlation coefficient (r) will be +1 only if all the data
lie on a perfectly horizontal straight line.
- The correlation coefficient (r) measures the fraction of
outliers that appear in a scatterplot.
- The correlation coefficient (r) is a unit-less number and must
always lie between –1 and +1, inclusive
B. An entomologist writes an article in a scientific journal
which claims that fewer than 10 in ten thousand male fireflies are
able to produce light due to genetic mutation. Identify the Type I
error for the test.
(2)
- The error of failing to reject that the true proportion is at
least 10 in ten thousand when it is actually less than 10 in ten
thousand.
- The error of rejecting that the true proportion is less than 10
in ten thousand when it is actually less than 10 in ten
thousand.
- The error of rejecting that the true proportion is at least 10
in ten thousand when it is actually at least 10 in ten
thousand.
- The error of failing to reject that the true proportion is less
than 10 in ten thousand when it is actually is at least 10 in ten
thousand.
C. What does the correlation coefficient (r) measure?
(2)
- Whether there is a relationship between two variables
- Whether or not a scatter diagram shows an interesting
pattern
- Whether a cause and effect relation exists between two
variables
- The strength of any straight line relation between two
variables
D.Which statement is true for any density
curve?
(2)
- It is symmetric.
- The total area under the curve is one.
- It must either steadily rise or steadily fall, since it cannot
do both.
- It has all of these properties.