When in a distribution of 10 numerical values, the last is increased by ten units, the variance is modified How good is the regression
(Y)/(x):y=1.5x-4;(x)/(Y):y=2x+2
Quite Good.
Rather Bad.
There is insufficient information
Very Bad.
The covariance is a value of dispersion calculated by:
Obtaining the mean of one variable times the other minus the square of the mean.
Obtaining the mean of squares minus the square of the mean.
Obtaining the mean of one variable times the other minus the multiplication of both means
Obtaining the sum of squares minus the mean.
The interquartilic range marks:
Q2-Q3.
The central
50% of data.
Q1-Q2.
The outer
50% of data.
The units of the standard deviation have the peculiarity of:
Being the squares of those of the variable.
The standard deviation has its own units.
Being those of the variable.
The standard deviation has no units. In New York State,
48% of all teenagers own a skateboard and
39% of all teenagers
own a skateboard and roller blades. What is the probability that a teenager owns roller
blades given that the teenager owns a skateboard?
87%
81%
123%
None of the above.
At a middle school,
18% of all students play football and basketball and
32% of all
students play football. What is the probability that a student plays basketball given
that the student plays football?
56%
178%
50%
None of the above.
In the United States,
56% of all children get an allowance and
41% of all children get an
allowance and do household chores. What is the probability that a child does
household chores given that the child gets an allowance?
137%
97%
73%
None of the above.
In Europe,
88% of all households have a television.
51% of all households have a
television and a VCR. What is the probability that a household has a VCR given that it
has a television?
173%
58%
42%
None of the above. Out of these regression lines which has
R^(2)=0.8 ?
(y)/(x):y=10x-2;(x)/(y):y-8x=3
(y)/(x):y-10x-2=0;(x)/(y):y+8x=0
(y)/(x):y-8x=2;(x)/(y):y=10x-5
(y)/(x):y-8x-5=0;(x)/(y):y=-10x-7
Two suppliers offer a machine part with the required 1" diameter. Samples indicate that supplier A's
product has a standard deviation of
0.12in. and supplier B's product has a standard deviation of
0.15in.
Which of the following statements is true?
A offers a more homogeneous product.
B offers a more homogeneous product.
The standard deviation has no relationship to the quality of the product.
Only the mean is important in buying the machine part.
True or False? If False, correct it. The standard deviation is a point in a distribution.
True
False. Correction:
True or false? If false, explain why. If the standard deviation of a set of scores is zero, all the scores have
the same value.
True
False. Why?:
In a regression between two variables
x and
Y there are two regression lines that share a single point:
(\bar{x} (,)/(b)ar (y))
(Sx,Sy)
This is untrue, they share two points:
(\bar{x} (,)/(b)ar (y)) and (Sx,Sy).
This untrue, they share no points.
by:
The value is not modified.
One unit.
Ten units.
There is insufficient information
Which of the following is not a measure of variability in a data set?
The range
The variance
The standard deviation
None of the above
Which of the following pairs are truly regression lines?
Y+x=1;-Y+2x=3
Y=x-1;Y+2x=3
-Y+x=1;Y+2x=3
Y-x=1;Y=2x-3
Which of these isn't a value for the linear correlation coefficient of a regression, R:
0.2
-0.8
0
1.1
The common point for both regression lines is:
(S_(x)^(2),S_(y)^(2))
(\alpha _(10),\alpha _(01))
(S_(xy),S_(xy))
(S_(x),S_(y))
The ratio of both slopes
\beta _(1) and
\beta _(2) is:
R^(2)
(S_(y)^(2))/(S_(x)^(2))
(x)/(Y)
(S_(x)^(2))/(S_(y)^(2))
