STAT 1000 EXAM 5 QUESTIONS AND 100%
CORRECT ANSWERS!!
What is a mathematical model?
it is an idealized description of data
ex: "perfect" symmetric curve
What is easier to work with, smooth curve or histogram?
smooth curve
The area under the curve represents...
the proportion of observations falling in our range of interest
What is a density curve?
The curve describing the overall shape of a distribution
3 properties of density curves...
1) the curve lies strictly on or above the x-axis
2) the total area underneath the curve and above the x-axis is equal to 1
3)The curve is a function (it passes the "vertical line test")
What is the vertical line test?
Any vertical line will cross the curve no more than once
Density curves are used to describe the distribution of...
continuous variables for "infinite" (large) populations
What are some different density curves?
-normal distribution
-uniform distribution
-triangular distribution
What is a uniform distribution?
, When a known finite number of outcomes are equally likely to occur. When graphed as a
histogram of occurrences, it's a flat line. (all equally as tall)
What is a triangular distribution?
looks like a triangle
What is the median for a distribution described by a particular density curve?
is the point on the xaxis with area 0.5 under the curve to each side
What is the mean of a continuous distribution?
"balance point" along the x axis.
mean still follows...
The tail
The variance of a continuous distribution is the...
average squared deviation of an observation from the mean of the distribution
(measure of spread)
What is the sample mean vs population mean?
sample = average value of some variable for all units in a SAMPLe of the pop
pop= (u) is the average value of some variable for all units in the ENTIRE pop
What is pop standard deviation?
(o) sigma
What is pop variance?
o^2
What do s, s^2, o, and o^2 all have to be?
non-negative (greater than or equal to zero)
What is a parameter?
CORRECT ANSWERS!!
What is a mathematical model?
it is an idealized description of data
ex: "perfect" symmetric curve
What is easier to work with, smooth curve or histogram?
smooth curve
The area under the curve represents...
the proportion of observations falling in our range of interest
What is a density curve?
The curve describing the overall shape of a distribution
3 properties of density curves...
1) the curve lies strictly on or above the x-axis
2) the total area underneath the curve and above the x-axis is equal to 1
3)The curve is a function (it passes the "vertical line test")
What is the vertical line test?
Any vertical line will cross the curve no more than once
Density curves are used to describe the distribution of...
continuous variables for "infinite" (large) populations
What are some different density curves?
-normal distribution
-uniform distribution
-triangular distribution
What is a uniform distribution?
, When a known finite number of outcomes are equally likely to occur. When graphed as a
histogram of occurrences, it's a flat line. (all equally as tall)
What is a triangular distribution?
looks like a triangle
What is the median for a distribution described by a particular density curve?
is the point on the xaxis with area 0.5 under the curve to each side
What is the mean of a continuous distribution?
"balance point" along the x axis.
mean still follows...
The tail
The variance of a continuous distribution is the...
average squared deviation of an observation from the mean of the distribution
(measure of spread)
What is the sample mean vs population mean?
sample = average value of some variable for all units in a SAMPLe of the pop
pop= (u) is the average value of some variable for all units in the ENTIRE pop
What is pop standard deviation?
(o) sigma
What is pop variance?
o^2
What do s, s^2, o, and o^2 all have to be?
non-negative (greater than or equal to zero)
What is a parameter?
