STT 231 Exam 2 Questions With Correct
Answers
what two conditions must be met in order for the CLT to apply for proportional
| | | | | | | | | | | | | | |
testing? - CORRECT ANSWER✔✔-1: sample must be independent and identically
| | | | | | | | | |
distributed; like random assignment/sampling | | |
2: sample must be sufficiently large
| | | | |
normal density curve - CORRECT ANSWER✔✔-symmetric about the mean μ; has
| | | | | | | | | | |
standard deviation σ; total area under the curve = 1.0; values of the random
| | | | | | | | | | | | | |
variable X on x-axis; probabilities are represented by areas under the curve;
| | | | | | | | | | |
what do the numbers in the N(0,1) equation represent? - CORRECT ANSWER✔✔-
| | | | | | | | | | |
the first number is the mean (mu), and the second is the SD (sigma)
| | | | | | | | | | | | |
what is the equation for a standard normal curve/distribution, and what do the
| | | | | | | | | | | | |
axes represent? - CORRECT ANSWER✔✔-N(0,1) the x axis represents z-scores,
| | | | | | | | | |
and the y is the probability
| | | | |
what is the domain for a standard normal curve? which particular interval are we
| | | | | | | | | | | | | |
interested in? - CORRECT ANSWER✔✔-the actual domain=infinite, but we are
| | | | | | | | | |
interested mostly in (mu +/- 3sigma) | | | | |
, difference between pnorm and qnorm commands - CORRECT ANSWER✔✔-
| | | | | | | |
pnorm: gives proportion/percent of data within the given range
| | | | | | | |
qnorm: gives the cutoff range for the percentile of data inputted
| | | | | | | | | |
what are the required arguments for pnorm? qnorm? - CORRECT ANSWER✔✔-
| | | | | | | | | |
pnorm(upper cutoff, mean, SD) | | |
qnorm(upper percentile cutoff, mean, SD) | | | |
when do you use the lower.tail=false argument? - CORRECT ANSWER✔✔-during
| | | | | | | | | |
p/qnorm commands, when you are interested in the right side distribution
| | | | | | | | | |
normal model for sampling distribution of pi hat - CORRECT ANSWER✔✔-still
| | | | | | | | | | |
follows the rule of standard normal curve (N(0,1)), but it uses N(pi, SE equation)
| | | | | | | | | | | | | |
because
what is standard error? how do you interpret the results? - CORRECT
| | | | | | | | | | | |
ANSWER✔✔-it measures how close the current sample data reflects the overall
| | | | | | | | | | |
population predicted data, a high standard error value represents that your
| | | | | | | | | | |
sample is not very reflective of the population and is very spread out, vice versa
| | | | | | | | | | | | | | |
for low
|
how do SE and sample size n relate? - CORRECT ANSWER✔✔-as n increases, SE
| | | | | | | | | | | | | |
decreases, inverse relationship. | |
normal model for a sampling distribution of x bar - CORRECT ANSWER✔✔-still
| | | | | | | | | | | |
N(0,1) template, but the mean is represented by mu, and the SD is sigma/square
| | | | | | | | | | | | | |
root of n
| |
Answers
what two conditions must be met in order for the CLT to apply for proportional
| | | | | | | | | | | | | | |
testing? - CORRECT ANSWER✔✔-1: sample must be independent and identically
| | | | | | | | | |
distributed; like random assignment/sampling | | |
2: sample must be sufficiently large
| | | | |
normal density curve - CORRECT ANSWER✔✔-symmetric about the mean μ; has
| | | | | | | | | | |
standard deviation σ; total area under the curve = 1.0; values of the random
| | | | | | | | | | | | | |
variable X on x-axis; probabilities are represented by areas under the curve;
| | | | | | | | | | |
what do the numbers in the N(0,1) equation represent? - CORRECT ANSWER✔✔-
| | | | | | | | | | |
the first number is the mean (mu), and the second is the SD (sigma)
| | | | | | | | | | | | |
what is the equation for a standard normal curve/distribution, and what do the
| | | | | | | | | | | | |
axes represent? - CORRECT ANSWER✔✔-N(0,1) the x axis represents z-scores,
| | | | | | | | | |
and the y is the probability
| | | | |
what is the domain for a standard normal curve? which particular interval are we
| | | | | | | | | | | | | |
interested in? - CORRECT ANSWER✔✔-the actual domain=infinite, but we are
| | | | | | | | | |
interested mostly in (mu +/- 3sigma) | | | | |
, difference between pnorm and qnorm commands - CORRECT ANSWER✔✔-
| | | | | | | |
pnorm: gives proportion/percent of data within the given range
| | | | | | | |
qnorm: gives the cutoff range for the percentile of data inputted
| | | | | | | | | |
what are the required arguments for pnorm? qnorm? - CORRECT ANSWER✔✔-
| | | | | | | | | |
pnorm(upper cutoff, mean, SD) | | |
qnorm(upper percentile cutoff, mean, SD) | | | |
when do you use the lower.tail=false argument? - CORRECT ANSWER✔✔-during
| | | | | | | | | |
p/qnorm commands, when you are interested in the right side distribution
| | | | | | | | | |
normal model for sampling distribution of pi hat - CORRECT ANSWER✔✔-still
| | | | | | | | | | |
follows the rule of standard normal curve (N(0,1)), but it uses N(pi, SE equation)
| | | | | | | | | | | | | |
because
what is standard error? how do you interpret the results? - CORRECT
| | | | | | | | | | | |
ANSWER✔✔-it measures how close the current sample data reflects the overall
| | | | | | | | | | |
population predicted data, a high standard error value represents that your
| | | | | | | | | | |
sample is not very reflective of the population and is very spread out, vice versa
| | | | | | | | | | | | | | |
for low
|
how do SE and sample size n relate? - CORRECT ANSWER✔✔-as n increases, SE
| | | | | | | | | | | | | |
decreases, inverse relationship. | |
normal model for a sampling distribution of x bar - CORRECT ANSWER✔✔-still
| | | | | | | | | | | |
N(0,1) template, but the mean is represented by mu, and the SD is sigma/square
| | | | | | | | | | | | | |
root of n
| |
