ISDS 361A STUDY GUIDE 2026 QUESTIONS AND SOLUTIONS RATED A.pdf

ISDS 361A STUDY GUIDE 2026 QUESTIONS AND
SOLUTIONS RATED A+
✔✔Standard Deviatipon - ✔✔= STDEV.P (Population)
= STDEV.S (Sample)

✔✔Coefficient of variation - ✔✔= (Standard Deviation/ mean)*100
- Percentage of value sample mean

✔✔z-score - ✔✔= (x-u)/ standard deviation (population)

✔✔Empirical rule - ✔✔Use only when it is the Normal Distribution
- 1 Standard deviation: 68%
- 2 Standard deviation: 95%
- 3 Standard deviation: 99.7%

✔✔Chebyshev's Theorem - ✔✔Applied for bi-modal, skew modal
- = ( 1 - (1/z^2) )*100

✔✔Random Sample - ✔✔a sample that fairly represents a population because each
member has an equal chance of inclusion

✔✔Discrete random sample - ✔✔- Distribution that outcome can be coount
- Give out exact number as result

✔✔Conitnuous random sample - ✔✔- Can get any number in between

✔✔probability distribution - ✔✔-Collection of all outcomes of random variable
(continuous)

✔✔Probablity - ✔✔A number that describes how likely it is that an event will occur

✔✔=Norm.Dist (x, population mean, standard deviation, True)
- P(x< X) - ✔✔- population that find probablity on the left side

✔✔=1 - NORM.DIST(x, population mean, Standard Deviation, TRUE)
- P(x> X) - ✔✔population that find probability on the right side

✔✔=Norm.Dist (x, population mean, standard deviation, True)- Norm.Dist (x, population
mean, standard deviation, True)

P( R< x< X) - ✔✔population that find probability in between

✔✔=Norm.s.Dist(z, true)

, P(z<Z) - ✔✔FInd the probablity by using z score (Left side)

✔✔=1- Norm.s.Dist(z, true)
P( z> Z) - ✔✔FInd the probablity by using z score (RIght side)

✔✔=Norm.s.Dist(z, true)- Norm.s.Dist(z, true) - ✔✔FInd the probablity by using z score
(in Betweeen)

✔✔=Norm.INV( probablity, population mean, standard deviation) - ✔✔Find x by using
probablity of the population ( left side)

✔✔=Norm.INV( 1- probablity, population mean, standard deviation) - ✔✔Find x by using
the probablity of the population ( right side)

✔✔Key tip - ✔✔- ">": Maximum, More than, At least; top 1%; top 2%;....
- "<": Minimum, Less than, At most

✔✔ Raw Data - ✔✔Collection of unprocessed Information
Doing with random sample: Randomly collect a small part from large population

✔✔Why random Sample - ✔✔All people (data) have equal chance to participate

✔✔Process of Making Decision - ✔✔Collect Data ---> Extract Data ----> Make Decision

✔✔Information - ✔✔Processed data by using statistic
Example: Mean
: Median
: Standard Deviation
: .....

✔✔Business Statistic - ✔✔The scientific process of transforming data into insights for
making better business decisions.

✔✔Descriptive Statistic - ✔✔Measure and describe characteristic of statistic.
Measure of: Location (mean, median, mode)
: Variability (Standard Deviation, Variance, Range)
: Relative (z-score, coefficient, variation)

✔✔Inferential Statistic - ✔✔Measure and use information to tell some fact about the
population

✔✔Nominal - ✔✔Qualitative data, no number
Example: Male and Female