Exam (elaborations)
STAT 400 Midterm Questions And Answers Latest Update
- Course
- STAT 400
- Institution
- Loyola University Of Maryland
STAT 400 Midterm Questions And Answers Latest Update
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Solution 2024/2025Pepper
STAT 400 Midterm Questions And Answers
Latest Update
process for data mining ANS✔✔ 1. business/research understanding
2. data understanding
3. data preparation
4. modeling
5. evaluation
6. deployment
data cleaning ANS✔✔ check for entry errors, missing value, outlier, currency
units consistent
handling missing data ANS✔✔ 1. replace w/ constant
2. replace with mean or mode (measures of spread reduced)
3. replace with random (create some impossible combos)
4. replace with imputed value
mean ANS✔✔ w. skewed data becomes less representative of the center.
sensitive to outliers
median ANS✔✔ resilient to outliers
mode ANS✔✔ not always associated with variable center
, Solution 2024/2025
Pepper
sample SD ANS✔✔ sqrt(∑(x-x(bar))^2/ n-1)
-sensitive to outliers
-typical distance b/w a field value and the mean
-most are 2 SD within mean
issue with non normal ANS✔✔ variable with greater range will have undue
influence on the results. dominate
min normalization ANS✔✔ X*= X-min(X)/ (max(X)-min(X))
0=min value
.5=mid value
1= max value
0-1 range
Z-score standardization ANS✔✔ Z-score= X-mean(x)/ SD(X)
-value below mean= negative z score
-avg value = 0 z score
decimal scaling ANS✔✔ X* = X/(10^d)
d= number of digits in the data value w/ the largest abs value
(-1 to 1)
normal distribution ANS✔✔ mean u, spread SD
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