gyu other questions you messed up chapter 1 - 3

Question 1

stratified random sampling

Answer 1

when important groups within a population are separately sampled

those samples are combined to form a full sample

Question 2

what is a nominative variable?

Answer 2

a qualitative variable with no meaningful ordering

Question 3

what is undercoverage?

Answer 3

occurs when some population elements are excluded from the process of selecting the sample

It results in being unbalanced

Question 4

what is nonresponse

Answer 4

occurs whenever some of the individuals who were supposed to be included don’t want to come or simply can’t

Question 5

what is the science of using a sample of measurements to make generalizations about the important aspects of a population of measurements?

Answer 5

statistical inference

Question 6

If we examine all of the population measurements, we say that we are conducting a:

Answer 6

census of the population

Question 7

what is a strata

Answer 7

In order to select a stratified random sample, we divide the population into nonoverlap-ping groups of similar elements (people, objects, etc.)

these groups are strata

Question 8

what is systematic sampling

Answer 8

an alternative to random sampling

In order to systematically select a sample of n elements without replacement from a frame of N elements, we divide N by n and round the result down to the nearest whole number

Calling the rounded result ℓ, we then randomly select one element from the first ℓ elements in the frame—this is the first element in the systematic sample

The remaining elements in the sample are obtained by selecting every ℓth element following the first (randomly selected) element

Question 9

what are the flaws of multiple choice survey questions?

Answer 9

may fail to discover the reasons underlying a respondent’s choice of a particular answer

Question 10

what are the flaws of dichotomous survey questions?

Answer 10

possible responses are quite limited

Question 11

what are the flaws of open-ended survey questions?

Answer 11

can be difficult to evaluate and summarize

Question 12

what is a ratio variable

Answer 12

a quantitative variable measured on a scale such that ratios of its values are meaningful and there is an inherently defined zero value

variables such as salary, height, weight, time, and distance are ratio variables

Question 13

what is an interval variable

Answer 13

quantitative variable where ratios of its values are not meaningful and there is not an inherently defined zero value

Temperature (on the Fahrenheit scale) is an interval variable

Question 14

what does a frequency distribution do

Answer 14

summarizes the number of items in each number of several non overlapping classes

Question 15

what does a frequency polygon do

Answer 15

useful for comparing several distributions

Question 16

what is the cumulative relative frequency

Answer 16

when all the relative frequencies equal to 1.00

Question 17

how do you construct a frequency polygon

Answer 17

you plot points above each class’ midpoint at a height equal to the relative frequency of a class

Question 18

how do you calculate the number of classes in a frequency distribution

Answer 18

2^k > n

k is the number of classes

Question 19

what type of chart can:

identify quality problems

suggest where a process needs improvement

help prioritize problem solving activities

Answer 19

a Pareto chart

Question 20

when would you use the Chebysev theorem?

Answer 20

when the curve is not mound shaped (for ex: two peaks)+

also not much skewness

the population has mean and standard deviation

Question 21

for the chebysev theorem, why would you not use a mound shape for it

Answer 21

because you can use the Empirical rule

Question 22

what does the Chebysev theorem tell you?

Answer 22

how many standard deviations the x is from the mean and shit

same as empirical rule, but with more fucked up shid

Question 23

what does the Chebysev theorem tell you?

Answer 23

how many standard deviations the x is from the mean and shit

how much of the population lies between a certain amount if standard deviations

same as empirical rule, but with more fucked up shid

Question 24

why would it not be okay to use any formula using standard deviation for a population with a lot of skewdness

Answer 24

the standard deviation will be inflated as shied

Question 25

what should you use instead of a formula using a standard deviation for a population skewed af

Answer 25

percentiles is gyuer

Question 26

what is the calculation of the coefficient of variation

Answer 26

(standard deviation / mean) * 100

Question 27

when can you use the empirical rule

Answer 27

on mount shaped distributions

normal distributions (mount shaped be included)

Question 28

what is a obtained from a sample that is used to estimate a similar value from a larger population?

Answer 28

a point estimate

Question 29

what is the covariance

Answer 29

strength of the linear relationship between x and y

Question 30

when do we use the sample covariance?

Answer 30

when we wish to measure the strength of the linear association between two numerical values

Question 31

what is grouped data

Answer 31

the only data available are in the form of a frequency distribution or a histogram

it does not give the individual measurements in a data set

Question 32

when approximating the variance for grouped data, what is used to approximate the measurements in a class

Answer 32

the midpoint of each class

Question 33

when do you use a weighted mean

Answer 33

when it makes sense to give different measurements unequal weights

Question 34

how do you use the weighted mean

Answer 34

multiplying each measurement by its weight

summing the resulting products

and dividing the resulting sum by the sum of the weights

Question 35

what is the best measure of central tendency when outliers are present?

Answer 35

the mode

Question 36

if the measurements of a data set (or curve) is more spread out, how is the variance

Answer 36

bigger

Question 37

if the measurements of a data set (or curve) is more spread out, how is the standard deviation

Answer 37

bigger

Question 38

the raw deviations from the mean sum to what?

Answer 38

0

Question 39

how do you calculate outliers

Answer 39

outside lower limit: Q1 - 1.5*IQR

outside upper limit: Q3 + 1.5*IQR