Statistics Exam 1

coefficient of variation

(standard deviation/ mean) X 100

Empirical rule = 1

68%

K=2 in Chebyshevs theorem

75%

K=3 in Chebyshev

88.9

Empirical rule = 2

95%

Empirical rule = 3

99.7

stratified sampling

A few members from each stratum (or group) are randomly chosen

Variance is:

A measure of how far the data values are spread from the mean

standard deviation

A measure of how much we might expect a typical member of the data set to differ from the mean

Cluster sampling

All members from a few randomly chosen clusters (or groups) are selected.

Population parameter

An assumption of the population not the statistics found in the samplw

Interval level

Applies to data that can be arranged in order. In addition, differences between data values are meaningful. Quantitative

Continuous data

Can take on any value and are usually measurements

Each member of a few groups

Cluster sample

Quantitative data

Counts or measurements

Simple random sampling

Every SAMPLE of the population has an equal chance of being selected.

Random sampling

Every member of the population has an equal chance of being selected

systematic sampling

Every other member of the population is chosen

confounding variable

Factors other than the treatment that cause an effect on the subjects of an experimenr

inferential statistics

Infers what you found to larger population

Indicate the level of measurement for the data set described. Boiling points (in degrees Celsius) for various substances

Interval

qualitative data

Labels or descriptions of traits

class midpoint formula

Lower class boundary + upper class boundary / 2

Use (blank) for quantitative data that is not skewed A) mode B) median C) mean

Mean

Use (blank) for SKEWED quantitative data A) mode B) median C) mean

Median

Use (blank) for qualitative/categorical data A) mode B) median C) mean

Mode

There is no mode when...

No numbers appear more than the others

Indicate the level of measurement for the data set described. Young children's answers to the question "What do you want to be when you grow up?"

Nominal

Nominal or ordinal: The genres of the music performed at the original Grammys in 1959

Nominal

Nominal or ordinal? The seat numbers on your concert tickets, such as A23 and A24

Ordinal

relative frequency

Percentage of the data set that falls into a particular class

Theta squared is

Population variance

Boiling points in degrees Celsius for various substances are an example of which type of data?

Quantitative

Discrete data

Quantitative data that can only take on particular values and are usually counts

How to find class width?

Range/number of classes

Consider the ages in whole years of US presidents when they were inaugurated. What level of measurement are these data?

Ratio level

Indicate the level of measurement for the data set described. Lengths of newborn babies

Ratio level

Sample is represented by

S

Convenience sampling

Sample is chosen by it is convenient for the researcher

S squares is

Sample variance

A few members of each group

Stratified sample

To find stand deviation you can...

Take the square root of variance

Population is represented by

Theta

True or false: the larger the standard deviation, the more spread out the data

True

True or false: the larger your variance the more your data is spread out

True

True or false: you always round the class width up

True

meta-analysis

a "study of studies" that combines the findings of multiple studies to arrive at a conclusion

double-blind experiment

an experiment in which neither the experimenter nor the participants know which participants received which treatment

Single blind experiment

an experiment in which the participants are unaware of who received the treatment

ratio level of measurement

applies to data that can be arranged in order. In addition, both differences between data values and ratios of data values are meaningful. Data at the ratio level have a true zero.

Relative frequency formula

class frequency / sum of all frequencies

Cross sectional study

data are collected at a single point in time

longitudinal study

data are gathered by following a particular group over a period of time.

ordinal level

data arranged in some order, but the differences between data values cannot be determined or are meaningless. Qualitative

case study

looks at multiple variables that affect a single event.

5 number summary

min, Q1, median, Q3, max

population variance formula

o~ ^2 = ∑ (x - µ)2 / N o~ ^2 is the population variance x is the value of a particular observation in the population µ is the arithmetic mean of the population N is the number of observation in the population

Eye colors are an example of which type of data?

qualitative

Nominal level data

qualitative data consisting of labels or names

Pounds gained by persons in your class during the first month of the semester are an example of which type of data?

quantitative

Sample Variance Formula

s^2 = ∑(x- x̄)^2 / n-1 s^2 is the sample variance x is the value of each observation in the sample x̄ is the mean of the sample n is the number of observations in the sample

control group

the group that does not receive the experimental treatment.

treatment group

the group that receives the treatment

class limits

the least and greatest number that can belong in a class

Cumulative frequency

the sum of the frequencies for that class and all previous classes

Class boundary

the value that lies halfway between the upper limit of one class and the lower limit of the next class

sample mean symbol

x̅

population mean symbol

μ