Statistics Test 1

Front 1

What are the symbols for population and sample mean?

Back 1

Front 2

What are the symbols for population and sample variance?

Back 2

Front 3

What are the symbols for population and sample standard deviation?

Back 3

Front 4

Define variance

Back 4

How far the population is spread about the mean

Front 5

Define standard deviation

Back 5

The square root of the variance.

Front 6

Define Parameter

Back 6

Descriptive Measure about a population

Front 7

Define statistic

Back 7

Descriptive Measure about a sample

Front 8

What are the 3 types of data

Back 8

Interval
Ordinal
Nominal

Front 9

What is the most appropriate measure of central location for interval data?

Back 9

mean, median, and/or mode are all appropriate

Front 10

What is the most appropriate measure of central location for ordinal data?

Back 10

Median

Front 11

What is the most appropriate measure of central location for nominal data?

Back 11

Mode

Front 12

According to the empirical rule, what percentage of all observations fall within:
1 standard deviation
2 standard deviations
3 standard deviations

Back 12

1. 68%
2. 95%
3. 99.7%

Front 13

Describe Chebysheff's theorum

Back 13

The proportion of observations in any sample or population that lie within K standard deviations of the mean is at least:

1-(1/K^2) for K>1

Front 14

What is type of distribution is the empirical rule used for?

What distribution is chebysheff's rule used for?

Back 14

Empirical: normal

Chebysheff: skewed

Front 15

How can variability be compared with multiple sets of interval data?

Back 15

By using the coefficient of variation?

Front 16

What is the formula for the coefficient of variation?

Back 16

CV = standard deviation/mean

Front 17

What does the interquartile range equal? What does this measure?

Back 17

Q3-Q1

Measures the spread of the middle 50% of the observations.

Front 18

What do large values of the interquartile range indicate?

Back 18

That first and third quartile are far apart and that there is high variability in the data.

Front 19

In a box plot, if the line is left of center, then the data is skewed______?

Back 19

Skewed to the right (or positively)

Front 20

In a box plot, if the line is right of center, then the data is skewed ______?

Back 20

Skewed to left (or negatively)

Front 21

In a box plot, what do points outside the whiskers represent?

Back 21

Outliers

Front 22

How are outliers identifified using the interquartile range?

Back 22

Outliers will exist

Above: Q1+1.5(IQR)
Below: Q1-1.5(IQR)

Front 23

What is the R^2 value?

Back 23

R^2 is the coefficient of determination. It is the proportion in the dependent variable explained by the independent variable.

Front 24

an R^2 value of .75 means...?

Back 24

.75 of Y (dependent) is caused by X (independent). .25 of Y is unexplained.

Front 25

What are the methods of data collection?

Back 25

direct observation
experiments
surveys
personal inteview
telephone interview

Front 26

What are the types of sampling plans?

Back 26

convenience sampling
Stratified
Proportional stratified
Cluster
Systematic

Front 27

Define cluster sampling

Back 27

First dividing population into clusters, then take random sample of clusters, then take random sample of elements in each cluster.

Front 28

Define systematic sampling

Back 28

Random every nth item selected.

Front 29

What are the types of errors in sampling. Define them.

Back 29

Sampling errors: when sample mean is different from population mean (margin of error)

Non-sampling error: error not caused by sampling

Front 30

What are the types of non sampling errors?

Back 30

Random errors - unpredictable. The larger the population the more random error cancels out.

Systematic error - error in question design, non-responsive, biased answers.

Front 31

What are the measures of reliability?

Back 31

Confidence and Significance Level

Front 32

Define confidence level

Back 32

The proportion of times an estimation procedure will be correct

Front 33

Define significance level

Back 33

How frequently a conclusion will be incorrect in the long run.

Front 34

A confidence level of 95% means that the significance level is______%

Back 34

CL or 95% = SL of 5%

Front 35

What are the 3 approaches to probability?

Back 35

Classical/Theoretical
Subjective Approach
Relative Frequency Approach

Front 36

Describe the classical approach to probability

Back 36

Can only use when events are equally likely

Front 37

Describe the relative frequency approach to probability

Back 37

Collect data, conduct an experiment, obtain and organize results.

P(a)=frequency/sample size

Approximate probabilities

Front 38

How do you find the number of marginal probabilities that exist in a table?

Back 38

Add the rows and columns to find the number of marginal probabilities

Front 39

What is the notation for the probability of event A given event B?

Back 39

P(A|B)

Front 40

How is it determined If event A and event B are independent?

Back 40

if P(A|B) = A, then A and B are independent.

Front 41

P(A|B) =

Back 41

P(A|B) = P(A and B)/P(B)

Front 42

If A and B are independent, the P(A and B) =

Back 42

P(A and B) = P(A) * P(B)

Front 43

If A and B are not independent, then P(A and B) =

Back 43

P(A and B) = P(A)*P(B|A)

Front 44

P(A or B) =

What kind of probability does this describe?

Back 44

P(A or B) = P(A) + P(B) - P(A and B)

Compound probability

Front 45

If events A and B are mutually exclusive, then P(A or B) =

Back 45

P(A or B) = P(A) + P(B)

Front 46

Class width =

Back 46

(largest observation - smallest observation)/number of rows desired

Front 47

Relative frequency =

Back 47

Relative frequency = frequency occurred in row divided by total sample frequencies.

Front 48

Cumulative relative frequency =

Back 48

Cumulative relative frequency = Relative frequency accumulated

Front 49

Cumulative frequency =

Back 49

Cumulative frequency = frequency accumulating

Front 50

What is an ogive?

Back 50

A cumulative frequency graph. Always goes upward, never downward. Uses relative frequency. It shows what percentage of the sample is below a certain number.

Front 51

What is a stem and leaf plot?

Back 51

A graphical depiction of observation in a sample. The first digit = Stem, Second digit = leaf.

Front 52

When is a histogram symmetric?

Back 52

When mean=median=mode

Front 53

When are histograms skewed to the right? left?

Back 53

skewed right = mean is to the right of median
skewed left = mean is to the left of median

Front 54

What are the 3 measures of variation?

Back 54

Range
Variance
Standard Deviation

Front 55

Class Width =

Back 55

(Largest observation - Smallest Oberservation)/class width