IDS 270 Exam 1 | 2024 Questions & Answers
| 100% Correct | Verified
What is the formula for finding residuals? - ✔✔y-yhat=residual
When do you know a residual graph is over predicting? - ✔✔When the point on the residual graph is
below the x-axis, meaning that it's negative.
When do you know a residual graph is under predicting? - ✔✔When the point on the residual graph is
above the x-axis, meaning it is a positive number
How do you know a relationship between x & y is positive? - ✔✔If the slope is positive, the graph is
positive, so that means it's a positive relationship between x & y
How can you characterize the strength of the relationship between x & y? - ✔✔By calculating (r)^2. The
closer r^2 is to 1, the stronger the relationship is.
If x increases by 1, what is the predication for the change in y? - ✔✔The change in y is dependent on the
amount of regression.
If you: roll even on a red die, and roll an odd on a green die, these are __________ - ✔✔independent
If you: roll an even on red and roll an odd on red, these are ____ - ✔✔disjoint
Formula for the union of two probabilities? - ✔✔Pr(A U B)= P(a) + P(b) - Pr(A and B)
Formula for: Pr(A and B)? - ✔✔P(a) * P(b)
How do you know if two parts to a probability problem are independent of each other? - ✔✔If Pr(A and
B) = P(a) * P(b) = Pr(A and B)
, Population Distribution - ✔✔Entire Population being used
Sample distribution - ✔✔Initial samples taken from population distribution
Sampling distribution - ✔✔Averages from all samples taken
What shape is related to Central Limit Theorem? - ✔✔Bell shape
Finding the Standard Deviation based on C.L.T - ✔✔S.D of population / Root( # in each sample
If you compare two spreads, which number will be a tighter spread, big or small number? - ✔✔Smaller
number
What method do you use in order to get: What % of test takers can expect 700 or less - ✔✔X --> Z --> %
Ex. General intelligence test has mean of 600, standard deviation of 60. what is percentile score for an
exam of 700 (what percent of test takers get 700 or less) (x < 700),
x is 700,
z= (700-600)/60= 1.66
Pr(z<1.66)
z= 1.6 on table a
left to right- on top is for hundreths place. which is .06
What method do you use in order to get: What score is necessary to reach 90th percentile - ✔✔% --> Z --
>X
ex.
general intelligence test mean of 600 and a standard deviation of 60. what score is necessary to reach
90th percentile?
.9 in BODY of table A is 1.28( the value is .8997 closest to .9) so solve 1.28=(x-600/60) leads to 676.8
| 100% Correct | Verified
What is the formula for finding residuals? - ✔✔y-yhat=residual
When do you know a residual graph is over predicting? - ✔✔When the point on the residual graph is
below the x-axis, meaning that it's negative.
When do you know a residual graph is under predicting? - ✔✔When the point on the residual graph is
above the x-axis, meaning it is a positive number
How do you know a relationship between x & y is positive? - ✔✔If the slope is positive, the graph is
positive, so that means it's a positive relationship between x & y
How can you characterize the strength of the relationship between x & y? - ✔✔By calculating (r)^2. The
closer r^2 is to 1, the stronger the relationship is.
If x increases by 1, what is the predication for the change in y? - ✔✔The change in y is dependent on the
amount of regression.
If you: roll even on a red die, and roll an odd on a green die, these are __________ - ✔✔independent
If you: roll an even on red and roll an odd on red, these are ____ - ✔✔disjoint
Formula for the union of two probabilities? - ✔✔Pr(A U B)= P(a) + P(b) - Pr(A and B)
Formula for: Pr(A and B)? - ✔✔P(a) * P(b)
How do you know if two parts to a probability problem are independent of each other? - ✔✔If Pr(A and
B) = P(a) * P(b) = Pr(A and B)
, Population Distribution - ✔✔Entire Population being used
Sample distribution - ✔✔Initial samples taken from population distribution
Sampling distribution - ✔✔Averages from all samples taken
What shape is related to Central Limit Theorem? - ✔✔Bell shape
Finding the Standard Deviation based on C.L.T - ✔✔S.D of population / Root( # in each sample
If you compare two spreads, which number will be a tighter spread, big or small number? - ✔✔Smaller
number
What method do you use in order to get: What % of test takers can expect 700 or less - ✔✔X --> Z --> %
Ex. General intelligence test has mean of 600, standard deviation of 60. what is percentile score for an
exam of 700 (what percent of test takers get 700 or less) (x < 700),
x is 700,
z= (700-600)/60= 1.66
Pr(z<1.66)
z= 1.6 on table a
left to right- on top is for hundreths place. which is .06
What method do you use in order to get: What score is necessary to reach 90th percentile - ✔✔% --> Z --
>X
ex.
general intelligence test mean of 600 and a standard deviation of 60. what score is necessary to reach
90th percentile?
.9 in BODY of table A is 1.28( the value is .8997 closest to .9) so solve 1.28=(x-600/60) leads to 676.8
